diff --git a/app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryPresenter.kt b/app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryPresenter.kt
index 55a8d6932..6fdc2707f 100755
--- a/app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryPresenter.kt
+++ b/app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryPresenter.kt
@@ -541,15 +541,27 @@ class LibraryPresenter(
     fun downloadUnreadChapters(mangas: List<Manga>) {
         mangas.forEach { manga ->
             launchIO {
-                /* SY --> */ val chapters = if (manga.isEhBasedManga()) {
-                    val chapter = db.getChapters(manga).executeOnIO().minByOrNull { it.source_order }
-                    if (chapter != null && !chapter.read) listOf(chapter) else emptyList()
-                } else if (manga.source == MERGED_SOURCE_ID) {
-                    (sourceManager.getOrStub(MERGED_SOURCE_ID) as MergedSource).getChaptersAsBlocking(manga).filter { !it.read }
-                } else /* SY <-- */ db.getChapters(manga).executeAsBlocking()
-                    .filter { !it.read }
+                if (manga.source == MERGED_SOURCE_ID) {
+                    val mergedSource = sourceManager.get(MERGED_SOURCE_ID) as MergedSource
+                    val mergedMangas = db.getMergedMangas(manga.id!!).executeAsBlocking()
+                    mergedSource
+                        .getChaptersAsBlocking(manga)
+                        .filter { !it.read }
+                        .groupBy { it.manga_id!! }
+                        .forEach ab@{ (mangaId, chapters) ->
+                            val mergedManga = mergedMangas.firstOrNull { it.id == mangaId } ?: return@ab
+                            downloadManager.downloadChapters(mergedManga, chapters)
+                        }
+                } else {
+                    /* SY --> */ val chapters = if (manga.isEhBasedManga()) {
+                        db.getChapters(manga).executeOnIO().minByOrNull { it.source_order }?.let { chapter ->
+                            if (!chapter.read) listOf(chapter) else emptyList()
+                        } ?: emptyList()
+                    } else /* SY <-- */ db.getChapters(manga).executeAsBlocking()
+                        .filter { !it.read }
 
-                downloadManager.downloadChapters(manga, chapters)
+                    downloadManager.downloadChapters(manga, chapters)
+                }
             }
         }
     }
@@ -623,10 +635,10 @@ class LibraryPresenter(
             if (source is MergedSource) {
                 val mergedMangas = db.getMergedMangas(manga.id!!).executeAsBlocking()
                 val sources = mergedMangas.distinctBy { it.source }.map { sourceManager.getOrStub(it.source) }
-                chapters.groupBy { it.manga_id }.forEach { map ->
-                    val mergedManga = mergedMangas.firstOrNull { it.id == map.key } ?: return@forEach
+                chapters.groupBy { it.manga_id }.forEach { (mangaId, chapters) ->
+                    val mergedManga = mergedMangas.firstOrNull { it.id == mangaId } ?: return@forEach
                     val mergedMangaSource = sources.firstOrNull { it.id == mergedManga.source } ?: return@forEach
-                    downloadManager.deleteChapters(map.value, mergedManga, mergedMangaSource)
+                    downloadManager.deleteChapters(chapters, mergedManga, mergedMangaSource)
                 }
             } else /* SY <-- */ downloadManager.deleteChapters(chapters, manga, source)
         }