diff --git a/agent_v0/agent_v1/core/executor.py b/agent_v0/agent_v1/core/executor.py
index 85733c2ca..8d12e16d8 100644
--- a/agent_v0/agent_v1/core/executor.py
+++ b/agent_v0/agent_v1/core/executor.py
@@ -1862,6 +1862,23 @@ class ActionExecutorV1:
                                     max_runtime_dialog_handles,
                                 )
                                 continue
+                    # P0.9 — double-check de stabilité post-transition (~0.5s).
+                    # Race condition observée sur replay_sess_56c10222 act 11 :
+                    # la fenêtre attendue ('Enregistrer sous') peut matcher
+                    # brièvement puis disparaître (dialog auto-fermée par un
+                    # clic parasite ultérieur, ou focus change OS). Sans
+                    # double-check, on valide une transition qui n'est plus là.
+                    if matched and expected_after and not runtime_dialog_handled:
+                        time.sleep(0.5)
+                        recheck_info = get_active_window_info()
+                        recheck_title = recheck_info.get("title", "")
+                        if not _matches_expected_window(recheck_title):
+                            logger.warning(
+                                f"P0.9 transition instable : matched '{post_title}' "
+                                f"puis '{recheck_title}' à T+0.5s ≠ '{expected_after}'"
+                            )
+                            matched = False
+                            post_title = recheck_title
                     if matched:
                         if runtime_dialog_handled:
                             result["warning"] = "runtime_dialog_handled_post_verify"