SDL_mixer: MIX_SetTrackGroup: Fixed doubly-linked list state when moving between groups.

SDL Commits
1 
From 8c516fcd2eca48262188426fbe75365ba4326346 Mon Sep 17 00:00:00 2001
From: "Ryan C. Gordon" <[EMAIL REDACTED]>
Date: Thu, 30 Oct 2025 10:18:19 -0400
Subject: [PATCH] MIX_SetTrackGroup: Fixed doubly-linked list state when moving
 between groups.

Fixes #762.
---
 src/SDL_mixer.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/SDL_mixer.c b/src/SDL_mixer.c
index 584e73b9..3beca55b 100644
--- a/src/SDL_mixer.c
+++ b/src/SDL_mixer.c
@@ -2730,6 +2730,7 @@ bool MIX_SetTrackGroup(MIX_Track *track, MIX_Group *group)
         if (oldgroup) {   // remove from current group, if in one.
             if (track->group_prev) {
                 track->group_prev->group_next = track->group_next;
+                track->group_prev = NULL;
             } else {
                 oldgroup->tracks = track->group_next;
             }