This bug was encountered after my group has completed last boss in Graven Deep.
If you're before last boss in the bubble underwater and get pulled to side boss (e.g. Chralzak, Sphere 9402-A), the sounds remain the same as you're still in the bubble underwater.
Moreover, exiting the dungeon does not repair sounds. I don't use any addons that may modify audio in any way.
The best way to reproduce this issue (at least 2 players are needed):
1. Complete the Graven Deep dungeon (or leave last boss but it's better to complete dungeon) without clearing side bosses.
2. Player A has to go through the diving portal and stay in a bubble underwater
3. While Player A is in the bubble underwater before last boss room, player B has to solve any logic riddle and start encounter for the side boss to pull player A.
4. Check sounds as a player A -
https://youtu.be/mmchj_8xQIc
5. As a player A, leave dungeon and try to talk with NPC. -
https://youtu.be/0SsS55u-ips
Note, you may also have to trigger some emotes before encounter (like /lute) but I don't think it's necessary.