Fix scroll jump on chapter resume with continuous horizontal mode

CHANGELOG.md

@@ -37,6 +37,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 - (**Reader**) Fix opening the previous/next chapter in the continuous horizontal mode with inverted reading direction
 - (**Reader**) Fix scroll preservation in continuous horizontal mode with righ to left reading direction
 - (**Reader**) Fix mobile progress bar previous/next button not being clickable in single page chapters
+- (**Reader**) Fix scroll position jumping on chapter resume in the continuous horizontal mode
 - (**Manga**) Fix dynamic manga page color theme not getting reset after leaving the manga page
 
 ## [20251230.01] (r2937) - 2025-12-30

src/features/reader/viewer/hooks/useReaderPreserveScrollPosition.ts

@@ -282,10 +282,12 @@ const usePreserveOnInfiniteScrollPreviousChapterInitialRender = (
             visibleChapters,
         );
 
+        const doesPreviousChapterExist = currentChapterIndex > 0;
         const isRenderOfPreviousChapter = currentPageIndex === 0;
 
         // only relevant when prepending content to the dom due to the resulting layout shift
-        const isFirstRenderOfPreviousChapter = !previousNextChapterVisibility.previous && isRenderOfPreviousChapter;
+        const isFirstRenderOfPreviousChapter =
+            doesPreviousChapterExist && !previousNextChapterVisibility.previous && isRenderOfPreviousChapter;
         if (!isFirstRenderOfPreviousChapter) {
             return false;
         }