diff --git a/src/modules/reader/components/overlay/progress-bar/ReaderProgressBar.tsx b/src/modules/reader/components/overlay/progress-bar/ReaderProgressBar.tsx
index 38560486..af0d28b6 100644
--- a/src/modules/reader/components/overlay/progress-bar/ReaderProgressBar.tsx
+++ b/src/modules/reader/components/overlay/progress-bar/ReaderProgressBar.tsx
@@ -169,7 +169,7 @@ const BaseReaderProgressBar = ({
                                     totalPages={pages.length}
                                     primaryPageLoadState={pageLoadStates[page.primary.index].loaded}
                                     secondaryPageLoadState={
-                                        !!page.secondary && pageLoadStates[page.secondary.index].loaded
+                                        page.secondary ? pageLoadStates[page.secondary.index].loaded : undefined
                                     }
                                     createProgressBarSlot={createProgressBarSlot}
                                 />
diff --git a/src/modules/reader/components/overlay/progress-bar/ReaderProgressBarSlotWrapper.tsx b/src/modules/reader/components/overlay/progress-bar/ReaderProgressBarSlotWrapper.tsx
index 11c088eb..7cd7e6de 100644
--- a/src/modules/reader/components/overlay/progress-bar/ReaderProgressBarSlotWrapper.tsx
+++ b/src/modules/reader/components/overlay/progress-bar/ReaderProgressBarSlotWrapper.tsx
@@ -48,12 +48,12 @@ export const ReaderProgressBarSlotWrapper = memo(
         isTrailingPage: boolean;
         totalPages: number;
         primaryPageLoadState: ReaderProgressBarProps['pageLoadStates'][number]['loaded'];
-        secondaryPageLoadState: ReaderProgressBarProps['pageLoadStates'][number]['loaded'];
+        secondaryPageLoadState: ReaderProgressBarProps['pageLoadStates'][number]['loaded'] | undefined;
         createProgressBarSlot: (
             page: ReaderProgressBarProps['pages'][number],
             pagesIndex: number,
             primaryPageLoadState: ReaderProgressBarProps['pageLoadStates'][number]['loaded'],
-            secondaryPageLoadState: ReaderProgressBarProps['pageLoadStates'][number]['loaded'],
+            secondaryPageLoadState: ReaderProgressBarProps['pageLoadStates'][number]['loaded'] | undefined,
             isCurrentPage: boolean,
             isLeadingPage: boolean,
             isTrailingPage: boolean,