diff --git a/app/src/main/java/eu/kanade/tachiyomi/data/download/DownloadCache.kt b/app/src/main/java/eu/kanade/tachiyomi/data/download/DownloadCache.kt
index d5c3c9fd08..94d57d292a 100644
--- a/app/src/main/java/eu/kanade/tachiyomi/data/download/DownloadCache.kt
+++ b/app/src/main/java/eu/kanade/tachiyomi/data/download/DownloadCache.kt
@@ -77,7 +77,7 @@ class DownloadCache(
 
         checkRenew()
 
-        val files = mangaFiles[manga.id] ?: return false
+        val files = mangaFiles[manga.id]?.toSet() ?: return false
         return files.any { file -> provider.getValidChapterDirNames(chapter).any {
             it.toLowerCase() == file.toLowerCase()
         } }
diff --git a/app/src/main/java/eu/kanade/tachiyomi/ui/manga/MangaDetailsController.kt b/app/src/main/java/eu/kanade/tachiyomi/ui/manga/MangaDetailsController.kt
index 6a815565f5..5727c816eb 100644
--- a/app/src/main/java/eu/kanade/tachiyomi/ui/manga/MangaDetailsController.kt
+++ b/app/src/main/java/eu/kanade/tachiyomi/ui/manga/MangaDetailsController.kt
@@ -275,7 +275,8 @@ class MangaDetailsController : BaseController,
     }
 
     private fun setInsets(insets: WindowInsets, appbarHeight: Int, offset: Int) {
-        recycler?.updatePaddingRelative(bottom = insets.systemWindowInsetBottom)
+        val recycler = recycler ?: return
+        recycler.updatePaddingRelative(bottom = insets.systemWindowInsetBottom)
         headerHeight = appbarHeight + insets.systemWindowInsetTop
         swipe_refresh.setProgressViewOffset(false, (-40).dpToPx, headerHeight + offset)
         // 1dp extra to line up chapter header and manga header
diff --git a/app/src/main/java/eu/kanade/tachiyomi/ui/recent_updates/RecentChapterHolder.kt b/app/src/main/java/eu/kanade/tachiyomi/ui/recent_updates/RecentChapterHolder.kt
index 76b86eebf0..b24a3ab0e4 100644
--- a/app/src/main/java/eu/kanade/tachiyomi/ui/recent_updates/RecentChapterHolder.kt
+++ b/app/src/main/java/eu/kanade/tachiyomi/ui/recent_updates/RecentChapterHolder.kt
@@ -1,5 +1,6 @@
 package eu.kanade.tachiyomi.ui.recent_updates
 
+import android.app.Activity
 import android.view.View
 import androidx.core.content.ContextCompat
 import com.bumptech.glide.load.engine.DiskCacheStrategy
@@ -69,13 +70,12 @@ class RecentChapterHolder(private val view: View, private val adapter: RecentCha
         }
 
         // Set cover
-        GlideApp.with(itemView.context).clear(manga_cover)
-        if (!item.manga.thumbnail_url.isNullOrEmpty()) {
-            GlideApp.with(itemView.context)
-                    .load(item.manga)
-                    .diskCacheStrategy(DiskCacheStrategy.RESOURCE)
-                    .circleCrop()
-                    .into(manga_cover)
+        if ((view.context as? Activity)?.isDestroyed != true) {
+            GlideApp.with(itemView.context).clear(manga_cover)
+            if (!item.manga.thumbnail_url.isNullOrEmpty()) {
+                GlideApp.with(itemView.context).load(item.manga)
+                    .diskCacheStrategy(DiskCacheStrategy.RESOURCE).circleCrop().into(manga_cover)
+            }
         }
 
         val chapterColor = ChapterUtil.chapterColor(itemView.context, item)
diff --git a/app/src/main/java/eu/kanade/tachiyomi/ui/source/SourceController.kt b/app/src/main/java/eu/kanade/tachiyomi/ui/source/SourceController.kt
index 7fdb2d7618..54a9a91c1d 100644
--- a/app/src/main/java/eu/kanade/tachiyomi/ui/source/SourceController.kt
+++ b/app/src/main/java/eu/kanade/tachiyomi/ui/source/SourceController.kt
@@ -151,17 +151,19 @@ class SourceController : NucleusController<SourcePresenter>(),
             }
 
             override fun onStateChanged(p0: View, state: Int) {
-                val ext_bottom_sheet = ext_bottom_sheet ?: return
-                if (state == BottomSheetBehavior.STATE_EXPANDED) activity?.appbar?.y = 0f
+                val extBottomSheet = ext_bottom_sheet ?: return
+                if (state == BottomSheetBehavior.STATE_EXPANDED) {
+                    activity?.appbar?.y = 0f
+                }
                 if (state == BottomSheetBehavior.STATE_EXPANDED ||
                     state == BottomSheetBehavior.STATE_COLLAPSED) {
-                    sheet_layout.alpha =
+                    sheet_layout?.alpha =
                         if (state == BottomSheetBehavior.STATE_COLLAPSED) 1f else 0f
                     showingExtensions = state == BottomSheetBehavior.STATE_EXPANDED
                     setTitle()
                     if (state == BottomSheetBehavior.STATE_EXPANDED)
-                        ext_bottom_sheet.fetchOnlineExtensionsIfNeeded()
-                    else ext_bottom_sheet.shouldCallApi = true
+                        extBottomSheet.fetchOnlineExtensionsIfNeeded()
+                    else extBottomSheet.shouldCallApi = true
                     activity?.invalidateOptionsMenu()
                 }
 
diff --git a/app/src/main/java/eu/kanade/tachiyomi/ui/source/browse/BrowseSourceController.kt b/app/src/main/java/eu/kanade/tachiyomi/ui/source/browse/BrowseSourceController.kt
index f356d4124b..6ec5fe72f9 100644
--- a/app/src/main/java/eu/kanade/tachiyomi/ui/source/browse/BrowseSourceController.kt
+++ b/app/src/main/java/eu/kanade/tachiyomi/ui/source/browse/BrowseSourceController.kt
@@ -190,7 +190,7 @@ open class BrowseSourceController(bundle: Bundle) :
         recycler.adapter = adapter
 
         scrollViewWith(recycler, true, afterInsets = { insets ->
-            fab.updateLayoutParams<ViewGroup.MarginLayoutParams> {
+            fab?.updateLayoutParams<ViewGroup.MarginLayoutParams> {
                 bottomMargin = insets.systemWindowInsetBottom + 16.dpToPx
             }
         })