diff --git a/www/js/diary/timelineHelper.ts b/www/js/diary/timelineHelper.ts
index 383a78bc4..00d376a52 100644
--- a/www/js/diary/timelineHelper.ts
+++ b/www/js/diary/timelineHelper.ts
@@ -318,7 +318,7 @@ const points2TripProps = function (locationPoints) {
     inferred_labels: [],
     locations: locations,
     source: 'unprocessed',
-    start_fmt_time: startTime.toISO,
+    start_fmt_time: startTime.toISO(),
     start_local_dt: dateTime2localdate(startTime, startPoint.metadata.time_zone),
     start_ts: startPoint.data.ts,
     user_input: {},