diff --git a/src/renderer/src/components/cmd-j/task-search-activation.test.ts b/src/renderer/src/components/cmd-j/task-search-activation.test.ts
index 3c70fcdcb4e..a74dbbd6119 100644
--- a/src/renderer/src/components/cmd-j/task-search-activation.test.ts
+++ b/src/renderer/src/components/cmd-j/task-search-activation.test.ts
@@ -27,7 +27,16 @@ it('uses the attachment source owner when a workspace executes on a different ho
 it('rejects source host/account/site collisions even when the issue URL matches', () => {
   for (const source of [
     { ...jiraTaskSource, hostId: 'runtime:other' as const },
-    { ...jiraTaskSource, accountLabel: 'someone@example.com' },
+    // Another login on the same site has its own siteId.
+    {
+      ...jiraTaskSource,
+      providerIdentity: {
+        provider: 'jira' as const,
+        siteId: 'other-site-second-login',
+        siteUrl: 'https://other.atlassian.net',
+        projectKey: 'DEMO'
+      }
+    },
     {
       ...jiraTaskSource,
       providerIdentity: {
@@ -45,6 +54,15 @@ it('rejects source host/account/site collisions even when the issue URL matches'
   }
 })
 
+it('treats the Jira account label as display-only', () => {
+  const workspace = makeWorktree('labeled', 'Display name label', {
+    linkedItems: [
+      { ...attachment, taskSourceContext: { ...jiraTaskSource, accountLabel: 'Other' } }
+    ]
+  })
+  expect(findCmdJTaskWorkspace(jiraTaskResult, [workspace])).toBe(workspace)
+})
+
 it('rejects bare legacy identifiers and other Jira origins', () => {
   const bare = makeWorktree('bare', 'Unscoped', {
     linkedWorkItem: {
diff --git a/src/renderer/src/components/cmd-j/task-search-activation.ts b/src/renderer/src/components/cmd-j/task-search-activation.ts
index 6a11b89f259..f6a431327f0 100644
--- a/src/renderer/src/components/cmd-j/task-search-activation.ts
+++ b/src/renderer/src/components/cmd-j/task-search-activation.ts
@@ -13,7 +13,10 @@ import {
 } from '@/lib/new-workspace'
 import { buildLinearIssueLinkedWorkItem } from '@/lib/linear-linked-work-item'
 import type { Worktree } from '../../../../shared/worktree/types'
-import type { TaskSourceContext } from '../../../../shared/task-source-context'
+import {
+  haveConflictingTaskSourceAccounts,
+  type TaskSourceContext
+} from '../../../../shared/task-source-context'
 import type { CmdJTaskSearchResult } from './task-search-results'
 import { getJiraIssueWorkspaceSeed } from '../task-page-source-context'
 
@@ -21,30 +24,18 @@ function sourceMatches(source: TaskSourceContext, target: TaskSourceContext): bo
   if (source.provider !== target.provider || source.hostId !== target.hostId) {
     return false
   }
-  if (source.accountLabel && target.accountLabel && source.accountLabel !== target.accountLabel) {
+  if (haveConflictingTaskSourceAccounts(source, target)) {
     return false
   }
   const left = source.providerIdentity
   const right = target.providerIdentity
-  if (
+  return !(
     left?.provider === 'linear' &&
     right?.provider === 'linear' &&
     left.workspaceId &&
     right.workspaceId &&
     left.workspaceId !== right.workspaceId
-  ) {
-    return false
-  }
-  if (
-    left?.provider === 'jira' &&
-    right?.provider === 'jira' &&
-    left.siteId &&
-    right.siteId &&
-    left.siteId !== right.siteId
-  ) {
-    return false
-  }
-  return true
+  )
 }
 
 export function findCmdJTaskWorkspace(
diff --git a/src/renderer/src/components/cmd-j/task-search-requests.ts b/src/renderer/src/components/cmd-j/task-search-requests.ts
index 4718e6c1fac..130c34bc068 100644
--- a/src/renderer/src/components/cmd-j/task-search-requests.ts
+++ b/src/renderer/src/components/cmd-j/task-search-requests.ts
@@ -4,6 +4,7 @@ import { jiraSearchIssuesForTarget, jiraStatusForTarget } from '@/runtime/runtim
 import { ipcOrRuntimeTargetForHostId } from '@/runtime/runtime-client-target'
 import { gitLabApiFor } from '@/runtime/gitlab-owner-api'
 import { resolveJiraSourceHostId } from '@/lib/jira-source-host'
+import { getJiraAccountLabel } from '@/lib/jira-account-label'
 import {
   getRepoExecutionHostId,
   parseExecutionHostId,
@@ -257,7 +258,7 @@ async function searchJira(
       normalizeTaskSourceContext({
         ...source,
         providerIdentity: { provider: 'jira', siteId: issue.siteId ?? null, siteUrl: null },
-        accountLabel: status.viewer?.email ?? null
+        accountLabel: getJiraAccountLabel(status.viewer)
       })
     return itemSource
       ? [
diff --git a/src/renderer/src/components/new-workspace/use-jira-url-source.ts b/src/renderer/src/components/new-workspace/use-jira-url-source.ts
index f3a922a7171..7973a4dfc87 100644
--- a/src/renderer/src/components/new-workspace/use-jira-url-source.ts
+++ b/src/renderer/src/components/new-workspace/use-jira-url-source.ts
@@ -1,5 +1,6 @@
 import { useCallback, useEffect, useMemo, useRef, useState } from 'react'
 import { useAppStore } from '@/store'
+import { getJiraAccountLabel } from '@/lib/jira-account-label'
 import { assertRuntimeEnvironmentCapability } from '@/runtime/runtime-rpc-client'
 import {
   getMatchingJiraSites,
@@ -88,7 +89,7 @@ export function bindJiraIssueSourceContext(
       siteUrl: site.siteUrl,
       projectKey: issue.project.key
     },
-    accountLabel: site.email || site.displayName
+    accountLabel: getJiraAccountLabel(site)
   })
 }
 
diff --git a/src/renderer/src/components/sidebar/workspace-attachment-source-result.test.ts b/src/renderer/src/components/sidebar/workspace-attachment-source-result.test.ts
index 6a8482eb31b..b97540a5749 100644
--- a/src/renderer/src/components/sidebar/workspace-attachment-source-result.test.ts
+++ b/src/renderer/src/components/sidebar/workspace-attachment-source-result.test.ts
@@ -159,6 +159,27 @@ describe('attachment source conversion', () => {
       ).toBe(false)
     }
   )
+  it('detects a duplicate Jira link by site identity, not account label', () => {
+    const jira = (accountLabel: string, siteId: string): WorkspaceAttachment => ({
+      provider: 'jira',
+      type: 'issue',
+      number: 0,
+      jiraIdentifier: 'APP-1',
+      // Board URLs carry no provable issue identity, so source context decides.
+      url: 'https://acme.atlassian.net/jira/software/projects/APP/boards/1?selectedIssue=APP-1',
+      taskSourceContext:
+        normalizeTaskSourceContext({
+          provider: 'jira',
+          projectId: 'account-backed-task-source',
+          hostId: 'local',
+          providerIdentity: { provider: 'jira', siteId, siteUrl: 'https://acme.atlassian.net' },
+          accountLabel
+        }) ?? undefined
+    })
+    const saved = jira('dev@acme.example', 'site-a')
+    expect(isWorkspaceAttachmentLinked([saved], jira('Acme', 'site-a'))).toBe(true)
+    expect(isWorkspaceAttachmentLinked([saved], jira('dev@acme.example', 'site-b'))).toBe(false)
+  })
   it('only enriches the same symbolic identifier and URL source', () => {
     const task: WorkspaceAttachment = {
       provider: 'linear',
diff --git a/src/renderer/src/components/sidebar/workspace-attachment-source-result.ts b/src/renderer/src/components/sidebar/workspace-attachment-source-result.ts
index 7612bdd3557..382ca24262f 100644
--- a/src/renderer/src/components/sidebar/workspace-attachment-source-result.ts
+++ b/src/renderer/src/components/sidebar/workspace-attachment-source-result.ts
@@ -3,6 +3,7 @@ import type { Repo } from '../../../../shared/repo-types'
 import type { WorkspaceAttachment, Worktree } from '../../../../shared/worktree/types'
 import {
   buildTaskSourceContextFromRepo,
+  haveConflictingTaskSourceAccounts,
   normalizeTaskSourceContext,
   type TaskSourceContext,
   type TaskProvider
@@ -91,9 +92,7 @@ export function isWorkspaceAttachmentLinked(
       !newContext ||
       (oldContext.hostId === newContext.hostId &&
         oldContext.projectId === newContext.projectId &&
-        (!oldContext.accountLabel ||
-          !newContext.accountLabel ||
-          oldContext.accountLabel === newContext.accountLabel))
+        !haveConflictingTaskSourceAccounts(oldContext, newContext))
     )
   })
 }
diff --git a/src/renderer/src/components/task-page-jira-item-source-context.ts b/src/renderer/src/components/task-page-jira-item-source-context.ts
index be8ec6d4006..bdee8a35844 100644
--- a/src/renderer/src/components/task-page-jira-item-source-context.ts
+++ b/src/renderer/src/components/task-page-jira-item-source-context.ts
@@ -1,4 +1,5 @@
 import type { JiraIssue, JiraSite } from '../../../shared/jira-types'
+import { getJiraAccountLabel } from '@/lib/jira-account-label'
 import {
   normalizeTaskSourceContext,
   type TaskSourceContext
@@ -24,6 +25,6 @@ export function bindTaskPageJiraItemSourceContext(args: {
       siteUrl: site.siteUrl,
       projectKey: args.issue.project.key
     },
-    accountLabel: site.email || site.displayName || site.siteUrl
+    accountLabel: getJiraAccountLabel(site)
   })
 }
diff --git a/src/renderer/src/components/use-task-page-source-availability.ts b/src/renderer/src/components/use-task-page-source-availability.ts
index bee09bdb1e5..53c3ba38186 100644
--- a/src/renderer/src/components/use-task-page-source-availability.ts
+++ b/src/renderer/src/components/use-task-page-source-availability.ts
@@ -1,5 +1,6 @@
 import type { TaskPageRuntimeHostsModel } from './use-task-page-runtime-hosts'
 import { useCallback, useMemo } from 'react'
+import { getJiraAccountLabel } from '@/lib/jira-account-label'
 import type { Repo } from '../../../shared/repo-types'
 import {
   getTaskPageRepoSourceContext,
@@ -129,7 +130,7 @@ export function useTaskPageSourceAvailabilityPrelude(model: TaskPageRuntimeHosts
           siteId: selectedJiraSiteId && selectedJiraSiteId !== 'all' ? selectedJiraSiteId : null,
           siteUrl: selectedJiraSite?.siteUrl ?? null
         },
-        accountLabel: selectedJiraSite?.displayName ?? selectedJiraSite?.siteUrl ?? null
+        accountLabel: getJiraAccountLabel(selectedJiraSite)
       }),
     [
       accountBackedTaskSourceHostId,
diff --git a/src/renderer/src/lib/jira-account-label.ts b/src/renderer/src/lib/jira-account-label.ts
new file mode 100644
index 00000000000..8da69ddaa52
--- /dev/null
+++ b/src/renderer/src/lib/jira-account-label.ts
@@ -0,0 +1,9 @@
+/** Display label for a Jira login; its identity is the host plus providerIdentity.siteId. */
+export function getJiraAccountLabel(
+  account:
+    | { email?: string | null; displayName?: string | null; siteUrl?: string | null }
+    | null
+    | undefined
+): string | null {
+  return account?.email?.trim() || account?.displayName?.trim() || account?.siteUrl?.trim() || null
+}
diff --git a/src/renderer/src/lib/jira-issue-workspace-attachment.test.ts b/src/renderer/src/lib/jira-issue-workspace-attachment.test.ts
index 93c4cf245b4..dc38a603e27 100644
--- a/src/renderer/src/lib/jira-issue-workspace-attachment.test.ts
+++ b/src/renderer/src/lib/jira-issue-workspace-attachment.test.ts
@@ -112,7 +112,16 @@ describe('Jira workspace attachment identity', () => {
   it('rejects another execution host or Jira account but allows other repo contexts', () => {
     const workspace = linked('same-key')
     expect(matches([workspace], issue, { ...source, hostId: 'runtime:cloud' })).toEqual([])
-    expect(matches([workspace], issue, { ...source, accountLabel: 'another' })).toEqual([])
+    // Another login on the same site has its own siteId, and its issues carry it.
+    const otherSite: JiraSite = { ...site, id: 'site-a2', accountId: 'other-user' }
+    const otherLogin: TaskSourceContext = {
+      ...source,
+      providerIdentity: { provider: 'jira', siteId: otherSite.id, siteUrl: site.siteUrl }
+    }
+    expect(matches([workspace], { ...issue, siteId: otherSite.id }, otherLogin)).toEqual([])
+    expect(
+      collectLinkedJiraIssueRefs([workspace], [site, otherSite], otherSite.id, otherLogin)
+    ).toEqual([])
     expect(
       matches([workspace], issue, { ...source, projectId: 'other-repo-project', repoId: 'other' })
     ).toEqual([workspace])
@@ -138,6 +147,27 @@ describe('Jira workspace attachment identity', () => {
     })
     expect(matches([legacy])).toEqual([legacy])
   })
+  it('matches links whose account label differs from the Tasks page label', () => {
+    const emailLabeled = makeWorktree({
+      id: 'email-labeled',
+      repoId: 'repo',
+      linkedItems: [
+        {
+          provider: 'jira',
+          type: 'issue',
+          number: 0,
+          identifier: 'APP-1',
+          url: issue.url,
+          taskSourceContext: { ...source, accountLabel: 'dev@acme.example' }
+        }
+      ]
+    })
+    const tasksPage = { ...source, accountLabel: 'Acme' }
+    expect(matches([emailLabeled], issue, tasksPage)).toEqual([emailLabeled])
+    expect(collectLinkedJiraIssueRefs([emailLabeled], [site], 'all', tasksPage)).toMatchObject([
+      { key: 'APP-1', siteId: site.id }
+    ])
+  })
   it('matches account-scoped links in the all-sites view', () => {
     expect(matches([linked('one')], issue, { ...source, accountLabel: null })).toHaveLength(1)
   })
diff --git a/src/renderer/src/lib/jira-issue-workspace-attachment.ts b/src/renderer/src/lib/jira-issue-workspace-attachment.ts
index be805ba630a..7ac41683549 100644
--- a/src/renderer/src/lib/jira-issue-workspace-attachment.ts
+++ b/src/renderer/src/lib/jira-issue-workspace-attachment.ts
@@ -21,18 +21,9 @@ function jiraKey(item: WorkspaceAttachment): string | null {
     : (parseJiraIssueUrl(value)?.issueKey ?? null)
 }
 
+// Why host only: the login is matched by siteId below and the label is display-only; legacy links are local.
 function sameSource(item: WorkspaceAttachment, source?: TaskSourceContext | null): boolean {
-  if (!source) {
-    return true
-  }
-  const stored = item.taskSourceContext
-  // Legacy links were created by the desktop-owned Jira connection.
-  if ((stored?.hostId ?? 'local') !== source.hostId) {
-    return false
-  }
-  const storedAccount = stored?.accountLabel?.trim()
-  const selectedAccount = source.accountLabel?.trim()
-  return !storedAccount || !selectedAccount || storedAccount === selectedAccount
+  return !source || (item.taskSourceContext?.hostId ?? 'local') === source.hostId
 }
 
 function itemSite(item: WorkspaceAttachment) {
diff --git a/src/shared/task-source-context.ts b/src/shared/task-source-context.ts
index 1ae7636d6eb..cc54a689a12 100644
--- a/src/shared/task-source-context.ts
+++ b/src/shared/task-source-context.ts
@@ -142,6 +142,21 @@ export function areTaskSourceContextsEqual(
   )
 }
 
+/** Jira identity is siteId (site + login); its label is display-only. Callers match providers first. */
+export function haveConflictingTaskSourceAccounts(
+  a: Pick<TaskSourceContext, 'provider' | 'providerIdentity' | 'accountLabel'>,
+  b: Pick<TaskSourceContext, 'provider' | 'providerIdentity' | 'accountLabel'>
+): boolean {
+  if (a.provider === 'jira') {
+    const left = a.providerIdentity?.provider === 'jira' ? a.providerIdentity.siteId : null
+    const right = b.providerIdentity?.provider === 'jira' ? b.providerIdentity.siteId : null
+    return Boolean(left && right && left !== right)
+  }
+  const left = a.accountLabel?.trim()
+  const right = b.accountLabel?.trim()
+  return Boolean(left && right && left !== right)
+}
+
 export function getTaskSourceRuntimeSettings(
   context: Pick<TaskSourceContext, 'hostId'> | null | undefined
 ): Pick<GlobalSettings, 'activeRuntimeEnvironmentId'> {