diff --git a/.github/workflows/canary-staging.yml b/.github/workflows/canary-staging.yml
index f013ee21..9f1c31bb 100644
--- a/.github/workflows/canary-staging.yml
+++ b/.github/workflows/canary-staging.yml
@@ -159,14 +159,34 @@ jobs:
           ADMIN_TOKEN: ${{ secrets.MOLECULE_STAGING_ADMIN_TOKEN }}
         run: |
           set +e
+          # Slug prefix matches what test_staging_full_saas.sh emits
+          # in canary mode:
+          #   SLUG="e2e-canary-$(date +%Y%m%d)-${RUN_ID_SUFFIX}"
+          # Earlier this was `e2e-{today}-canary-` — that was the
+          # full-mode pattern (date FIRST, mode SECOND); canary slugs
+          # have mode FIRST, date SECOND. The mismatch silently
+          # never matched, leaving every cancelled-canary EC2 alive
+          # until the once-an-hour sweep eventually caught it
+          # (incident 2026-04-26 21:03Z: 1h25m EC2 leak before manual
+          # cleanup; same gap on three earlier cancellations today).
           orgs=$(curl -sS "$MOLECULE_CP_URL/cp/admin/orgs" \
             -H "Authorization: Bearer $ADMIN_TOKEN" 2>/dev/null \
             | python3 -c "
-          import json, sys
+          import json, sys, os
+          run_id = os.environ.get('GITHUB_RUN_ID', '')
           d = json.load(sys.stdin)
           today = __import__('datetime').date.today().strftime('%Y%m%d')
+          # Scope to slugs from THIS canary run when GITHUB_RUN_ID is
+          # available; the canary workflow sets E2E_RUN_ID='canary-\${run_id}'
+          # so the slug suffix is '-canary-\${run_id}-...'. Mirrors the
+          # full-mode safety net's per-run scoping (e2e-staging-saas.yml)
+          # added after the 2026-04-21 cross-run cleanup incident.
+          if run_id:
+              prefix = f'e2e-canary-{today}-canary-{run_id}'
+          else:
+              prefix = f'e2e-canary-{today}-'
           candidates = [o['slug'] for o in d.get('orgs', [])
-                        if o.get('slug','').startswith(f'e2e-{today}-canary-')
+                        if o.get('slug','').startswith(prefix)
                         and o.get('status') not in ('purged',)]
           print('\n'.join(candidates))
           " 2>/dev/null)