diff --git a/gateway/run.py b/gateway/run.py
index bd9847ab23..905a7763c5 100644
--- a/gateway/run.py
+++ b/gateway/run.py
@@ -2709,6 +2709,11 @@ def _reap_gateway_turn_processes(
     process. The newer turn snapshots its own baseline independently, so
     skipping here does not leave anything permanently unreaped.
     """
+    if not task_id:
+        # ProcessSession.task_id defaults to "" for sessionless callers, so a
+        # blank id would match (and kill) every unrelated empty-task process
+        # instead of this turn's own. Nothing session-scoped to reap.
+        return 0
     if is_still_current is not None:
         try:
             if not is_still_current():
@@ -24402,12 +24407,19 @@ class GatewayRunner(GatewayAuthorizationMixin, GatewayKanbanWatchersMixin, Gatew
                     done, _ = await asyncio.wait(
                         {_executor_task}, timeout=_POLL_INTERVAL
                     )
+                    if done:
+                        # Prefer the real result when the worker finished,
+                        # even if the watchdog fired in the same window: the
+                        # completed run already persisted its reply to session
+                        # history, so surfacing the "agent inactive" diagnostic
+                        # here would contradict the stored transcript. This
+                        # mirrors _abandon_timed_out_gateway_turn's own
+                        # worker_done-wins tiebreak (under cleanup_lock).
+                        response = _executor_task.result()
+                        break
                     if _turn_timeout_fired.is_set():
                         _inactivity_timeout = True
                         break
-                    if done:
-                        response = _executor_task.result()
-                        break
                     # Agent still running — check inactivity.
                     _agent_ref = agent_holder[0]
                     _idle_secs = 0.0
diff --git a/tests/gateway/test_abandoned_turn_process_cleanup.py b/tests/gateway/test_abandoned_turn_process_cleanup.py
index 67e62ffae8..c63a930b6a 100644
--- a/tests/gateway/test_abandoned_turn_process_cleanup.py
+++ b/tests/gateway/test_abandoned_turn_process_cleanup.py
@@ -188,6 +188,26 @@ def test_reap_fails_open_when_is_still_current_raises(monkeypatch):
     assert calls == [True]
 
 
+def test_reap_skips_empty_task_id(monkeypatch):
+    """ProcessSession.task_id defaults to "" — a blank turn id must never
+    fan out into killing unrelated sessionless processes (#76188 review)."""
+    calls = []
+    monkeypatch.setattr(
+        process_registry,
+        "kill_started_since",
+        lambda *_a, **_k: calls.append(True) or 1,
+    )
+
+    killed = _reap_gateway_turn_processes(
+        "",
+        frozenset(),
+        source="gateway_turn_timeout",
+    )
+
+    assert killed == 0
+    assert calls == []
+
+
 def test_timeout_abandon_propagates_is_still_current_to_the_reap(monkeypatch):
     agent = _IdleAgent()
     worker_done, timeout_fired, cleanup_lock = _state()