diff --git a/modules/mpv-player/android/src/main/java/expo/modules/mpvplayer/MPVLayerRenderer.kt b/modules/mpv-player/android/src/main/java/expo/modules/mpvplayer/MPVLayerRenderer.kt
index b026c6b8..241d3cdd 100644
--- a/modules/mpv-player/android/src/main/java/expo/modules/mpvplayer/MPVLayerRenderer.kt
+++ b/modules/mpv-player/android/src/main/java/expo/modules/mpvplayer/MPVLayerRenderer.kt
@@ -539,7 +539,9 @@ class MPVLayerRenderer(private val context: Context) : MPVLib.EventObserver {
 
             // Identity fields used to map a Jellyfin subtitle to the real track
             // (instead of fragile positional counting). `external` + `external-filename`
-            // uniquely identify a sub-added sidecar; `ff-index` aids embedded matching.
+            // uniquely identify a sub-added sidecar. `ff-index` is exposed for
+            // diagnostics / potential future exact-index matching; the current
+            // resolver matches embedded tracks by language/title, not ff-index.
             val external = mpv?.getPropertyBoolean("track-list/$i/external") ?: false
             track["external"] = external
             mpv?.getPropertyString("track-list/$i/external-filename")?.let {
diff --git a/modules/mpv-player/ios/MPVLayerRenderer.swift b/modules/mpv-player/ios/MPVLayerRenderer.swift
index e6a5e0a0..52e2ea67 100644
--- a/modules/mpv-player/ios/MPVLayerRenderer.swift
+++ b/modules/mpv-player/ios/MPVLayerRenderer.swift
@@ -786,7 +786,9 @@ final class MPVLayerRenderer {
 
             // Identity fields used to map a Jellyfin subtitle to the real track
             // (instead of fragile positional counting). `external` + `external-filename`
-            // uniquely identify a sub-added sidecar; `ff-index` aids embedded matching.
+            // uniquely identify a sub-added sidecar. `ff-index` is exposed for
+            // diagnostics / potential future exact-index matching; the current
+            // resolver matches embedded tracks by language/title, not ff-index.
             var external: Int32 = 0
             getProperty(handle: handle, name: "track-list/\(i)/external", format: MPV_FORMAT_FLAG, value: &external)
             track["external"] = external != 0
diff --git a/utils/jellyfin/subtitleUtils.ts b/utils/jellyfin/subtitleUtils.ts
index 7905d93c..3eeb2a66 100644
--- a/utils/jellyfin/subtitleUtils.ts
+++ b/utils/jellyfin/subtitleUtils.ts
@@ -91,7 +91,9 @@ export const compareTracksForMenu = (a: MediaStream, b: MediaStream): number =>
   Number(a.IsExternal ?? false) - Number(b.IsExternal ?? false) ||
   Number(b.IsForced ?? false) - Number(a.IsForced ?? false) ||
   Number(b.IsDefault ?? false) - Number(a.IsDefault ?? false) ||
-  (a.Index ?? 0) - (b.Index ?? 0);
+  // Missing Index sorts to the end (not 0, which would float it to the top and
+  // collide with a real Index 0).
+  (a.Index ?? Number.MAX_SAFE_INTEGER) - (b.Index ?? Number.MAX_SAFE_INTEGER);
 
 /**
  * Identity of a subtitle track as reported by the *player's real track list*