diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index 7eec27dfb..d5e305adb 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -110,7 +110,8 @@ jobs:
             tests/test_review_one_pr_ci_pending.bats \
             tests/test_release_registry.bats \
             tests/test_readme_refresh_helpers.bats \
-            tests/test_validate_personas.bats
+            tests/test_validate_personas.bats \
+            tests/test_dev_lead_concurrency_guard.bats
 
   template-drift:
     # Drift guard (#969): fail when a file committed in petry-projects/repo-template
diff --git a/tests/test_dev_lead_concurrency_guard.bats b/tests/test_dev_lead_concurrency_guard.bats
new file mode 100644
index 000000000..d37d0442e
--- /dev/null
+++ b/tests/test_dev_lead_concurrency_guard.bats
@@ -0,0 +1,27 @@
+#!/usr/bin/env bats
+# Regression guard for petry-projects/.github#443 (and #402/#450).
+#
+# The dev-lead issue-pickup race: GitHub fires one issues:labeled event per label
+# added in a single API call. If the reusable's per-issue concurrency used
+# cancel-in-progress:true, a later (non-dev-lead) labeled event could CANCEL the
+# run triggered by the dev-lead label before it dispatched — a "successful"
+# workflow that opened no PR. The fix (#450) is separate per-issue/per-PR lanes
+# with cancel-in-progress: false, so same-lane events queue behind the active run
+# and the pickup always finishes. These asserts fail loudly if anyone flips it back.
+
+REUSABLE=".github/workflows/dev-lead-reusable.yml"
+
+@test "dev-lead reusable concurrency is cancel-in-progress: false (#443/#450)" {
+  run grep -E '^[[:space:]]*cancel-in-progress:[[:space:]]*false[[:space:]]*$' "$REUSABLE"
+  [ "$status" -eq 0 ]
+}
+
+@test "dev-lead reusable has NO cancel-in-progress: true (would re-open the #443 race)" {
+  run grep -E '^[[:space:]]*cancel-in-progress:[[:space:]]*true[[:space:]]*$' "$REUSABLE"
+  [ "$status" -eq 1 ]
+}
+
+@test "dev-lead reusable routes issue events to a per-issue lane (#402 lanes)" {
+  run grep -F "format('dev-lead-issue-{0}', github.event.issue.number)" "$REUSABLE"
+  [ "$status" -eq 0 ]
+}