Merge branch 'master' into port-async-migration-routines

# Conflicts:
#	Jellyfin.Server/Migrations/Routines/20260915120000_MigrateRatingLevels.cs

1 files changed, 13 insertions, 2 deletions

diff --git a/Emby.Server.Implementations/Library/MediaSourceManager.cs b/Emby.Server.Implementations/Library/MediaSourceManager.cs
index 97e00177b6..e9bba05839 100644
--- a/Emby.Server.Implementations/Library/MediaSourceManager.cs
+++ b/Emby.Server.Implementations/Library/MediaSourceManager.cs
@@ -384,7 +384,13 @@ namespace Emby.Server.Implementations.Library
         {
             ArgumentNullException.ThrowIfNull(item);
 
-            var hasMediaSources = (IHasMediaSources)item;
+            // Clients can ask for the sources of an item that has none (a container queued by mistake).
+            if (item is not IHasMediaSources hasMediaSources)
+            {
+                throw new ArgumentException(
+                    string.Format(CultureInfo.InvariantCulture, "{0} {1} has no media sources and cannot be played.", item.GetType().Name, item.Id),
+                    nameof(item));
+            }
 
             var sources = hasMediaSources.GetMediaSources(enablePathSubstitution);
 
@@ -494,7 +500,12 @@ namespace Emby.Server.Implementations.Library
             {
                 var index = userData.SubtitleStreamIndex.Value;
                 // Make sure the saved index is still valid
-                if (index == -1 || source.MediaStreams.Any(i => i.Type == MediaStreamType.Subtitle && i.Index == index))
+                var savedStream = source.MediaStreams.FirstOrDefault(i => i.Type == MediaStreamType.Subtitle && i.Index == index);
+                // "Only forced" rules out full tracks entirely, so a remembered one must not resurrect them.
+                // The client reports whatever is playing, so an index remembered under another mode sticks forever otherwise.
+                if (index == -1
+                    || (savedStream is not null
+                        && (user.SubtitleMode != SubtitlePlaybackMode.OnlyForced || savedStream.IsForced)))
                 {
                     source.DefaultSubtitleStreamIndex = index;
                     return;