diff --git a/website/src/features/toolboxes/modules/TimerModule.jsx b/website/src/features/toolboxes/modules/TimerModule.jsx
index 08db967..6166b43 100644
--- a/website/src/features/toolboxes/modules/TimerModule.jsx
+++ b/website/src/features/toolboxes/modules/TimerModule.jsx
@@ -208,7 +208,7 @@ export function TimerModule({ toolboxId, moduleId, context }) {
         if (time && targetAt) countdown = { id: context.uid("timer"), label, type, time, targetAt };
       }
       if (type === "time_pattern") {
-        const pattern = timePartsToString(draft.pattern, { allowWildcard: true });
+        const pattern = hasTimePartValue(draft.pattern) ? timePartsToString(draft.pattern, { allowWildcard: true }) : "";
         if (pattern && getTimePatternTargetMs(pattern, now)) countdown = { id: context.uid("timer"), label, type, pattern };
       }
       if (type === "interval") {