diff --git a/src/domain/session/room/timeline/TimelineViewModel.js b/src/domain/session/room/timeline/TimelineViewModel.js
index 32a92cee..2f47ed77 100644
--- a/src/domain/session/room/timeline/TimelineViewModel.js
+++ b/src/domain/session/room/timeline/TimelineViewModel.js
@@ -78,6 +78,10 @@ export class TimelineViewModel extends ViewModel {
             this.tiles.unsubscribe(subscription);
         }
         if (!gapResult) {
+            /*
+            If gapResult resolves to false, then the gap is already being filled
+            and is thus being tracked for updates by a previous invocation of this method
+            */
             return;
         }
         if (!hasSeenUpdate) {