diff --git a/src/server.ts b/src/server.ts
index 1ef944f..8455382 100644
--- a/src/server.ts
+++ b/src/server.ts
@@ -90,7 +90,12 @@ export class WebhookServer {
 							snapshot_age_ms = Date.now() - ms;
 						}
 					}
-					const last_sync_ok = Metrics.get('last_sync_ok') ?? null;
+					const lastSyncMetric = Metrics.get('last_sync_ok');
+					let last_sync_ok: number | null = typeof lastSyncMetric === 'number' ? lastSyncMetric : null;
+					// Fallback: si no hay métrica, inferir a partir de la presencia de last_verified en grupos
+					if (last_sync_ok === null) {
+						last_sync_ok = lv ? 1 : 0;
+					}
 					const payload = { status: 'ok', active_groups, active_members, last_sync_at, snapshot_age_ms, last_sync_ok };
 					return new Response(JSON.stringify(payload), {
 						status: 200,