diff --git a/src/main/browser/snapshot-engine.test.ts b/src/main/browser/snapshot-engine.test.ts
index 17f5341b220..7282b432c1e 100644
--- a/src/main/browser/snapshot-engine.test.ts
+++ b/src/main/browser/snapshot-engine.test.ts
@@ -46,6 +46,25 @@ function node(
 }
 
 describe('buildSnapshot', () => {
+  it('keeps references routed to their own iframe session', async () => {
+    const tree = [
+      node('1', 'WebArea', 'page', { childIds: ['2'] }),
+      node('2', 'button', 'Submit', { backendDOMNodeId: 10 })
+    ]
+    const sessions = new Map([
+      ['frame-a', 'session-a'],
+      ['frame-b', 'session-b']
+    ])
+    const result = await buildSnapshot(makeSender(tree), sessions, () => makeSender(tree))
+    expect(result.refs.map((ref) => ref.ref)).toEqual(['@e1', '@e2', '@e3'])
+    expect([...result.refMap.values()].map((entry) => entry.sessionId)).toEqual([
+      undefined,
+      'session-a',
+      'session-b'
+    ])
+    expect([...result.refMap.values()].map((entry) => entry.backendDOMNodeId)).toEqual([10, 10, 10])
+  })
+
   it('returns empty snapshot for empty tree', async () => {
     const result = await buildSnapshot(makeSender([]))
     expect(result.snapshot).toBe('')
diff --git a/src/main/browser/snapshot-engine.ts b/src/main/browser/snapshot-engine.ts
index 5cdabbc9375..fb0fe5e19dd 100644
--- a/src/main/browser/snapshot-engine.ts
+++ b/src/main/browser/snapshot-engine.ts
@@ -61,7 +61,7 @@ export async function buildSnapshot(
   // Why: cross-origin iframes have their own AX trees accessible only through
   // their dedicated CDP session. Append their elements after the parent tree
   // so the agent can see and interact with iframe content.
-  const iframeRefSessions: { ref: string; sessionId: string }[] = []
+  const iframeRefSessions = new Map<string, string>()
   if (iframeSessions && makeIframeSender && iframeSessions.size > 0) {
     for (const [_frameId, sessionId] of iframeSessions) {
       try {
@@ -82,7 +82,7 @@ export async function buildSnapshot(
           const startRef = refCounter
           walkTree(iframeRoot, iframeNodeById, 1, entries, () => refCounter++)
           for (let i = startRef; i < refCounter; i++) {
-            iframeRefSessions.push({ ref: `@e${i}`, sessionId })
+            iframeRefSessions.set(`@e${i}`, sessionId)
           }
         }
       } catch {
@@ -120,12 +120,11 @@ export async function buildSnapshot(
       }
       lines.push(`${indent}[${entry.ref}] ${entry.role} "${displayName}"`)
       refs.push({ ref: entry.ref, role: entry.role, name: displayName })
-      const iframeSession = iframeRefSessions.find((s) => s.ref === entry.ref)
       refMap.set(entry.ref, {
         backendDOMNodeId: entry.backendDOMNodeId,
         role: entry.role,
         name: entry.name,
-        sessionId: iframeSession?.sessionId,
+        sessionId: iframeRefSessions.get(entry.ref),
         nth: total > 1 ? nth : undefined
       })
     } else {