diff --git a/apps/red-ui/src/app/modules/file-preview/services/file-data.service.ts b/apps/red-ui/src/app/modules/file-preview/services/file-data.service.ts
index 8a255b226..8cb8a5ece 100644
--- a/apps/red-ui/src/app/modules/file-preview/services/file-data.service.ts
+++ b/apps/red-ui/src/app/modules/file-preview/services/file-data.service.ts
@@ -270,7 +270,7 @@ export class FileDataService extends EntitiesService<AnnotationWrapper, Annotati
         const viewTime = timestampOf(viewedPage.viewedTime) - DELTA_VIEW_TIME;
         let changeOccurredAfterPageIsViewed = lastChange && timestampOf(lastChange.dateTime) > viewTime;
 
-        if (changeOccurredAfterPageIsViewed) {
+        if (changeOccurredAfterPageIsViewed !== undefined) {
             this.#markPageAsUnseenIfNeeded(viewedPage, lastChange.dateTime);
             return lastChange?.type;
         }
@@ -281,7 +281,7 @@ export class FileDataService extends EntitiesService<AnnotationWrapper, Annotati
         const processedTime = lastManualChange?.processedDate;
         changeOccurredAfterPageIsViewed = processedTime && timestampOf(processedTime) > viewTime;
 
-        if (changeOccurredAfterPageIsViewed) {
+        if (changeOccurredAfterPageIsViewed !== undefined) {
             this.#markPageAsUnseenIfNeeded(viewedPage, processedTime);
             return ChangeTypes.CHANGED;
         }