diff --git a/src/main/jira/__mocks__/jira-client-module.ts b/src/main/jira/__mocks__/jira-client-module.ts
index ee2e25f41bc..731c333e455 100644
--- a/src/main/jira/__mocks__/jira-client-module.ts
+++ b/src/main/jira/__mocks__/jira-client-module.ts
@@ -50,10 +50,9 @@ export async function loadJiraClientModule(
   })
 
   // Split modules must share one graph, request queue and credential cache per reset.
-  const [client, queue, api] = await Promise.all([
-    import('../client'),
-    import('../request-queue'),
-    import('../authenticated-request')
-  ])
+  // Why sequential: concurrent first imports can bypass Vitest's still-pending vi.doMock('os').
+  const client = await import('../client')
+  const queue = await import('../request-queue')
+  const api = await import('../authenticated-request')
   return { ...client, ...queue, ...api }
 }
diff --git a/src/renderer/src/lib/pane-manager/pane-tree-reparent-frame.test.ts b/src/renderer/src/lib/pane-manager/pane-tree-reparent-frame.test.ts
index 57b384eab9d..5bfc7189924 100644
--- a/src/renderer/src/lib/pane-manager/pane-tree-reparent-frame.test.ts
+++ b/src/renderer/src/lib/pane-manager/pane-tree-reparent-frame.test.ts
@@ -159,10 +159,9 @@ describe('insertPaneNextTo reparent frame', () => {
 
   it('passes pane drag active callbacks into dividers created during reorder', async () => {
     setupDocument()
-    const [{ insertPaneNextTo }, { createDivider }] = await Promise.all([
-      import('./pane-tree-ops'),
-      import('./pane-divider')
-    ])
+    // Why sequential: concurrent first imports can bypass Vitest's still-pending vi.mock registrations.
+    const { insertPaneNextTo } = await import('./pane-tree-ops')
+    const { createDivider } = await import('./pane-divider')
     const parent = createMockElement('pane-split')
     const source = createPane(1)
     const target = createPane(2)