Ender Dragon Death Sound played across dimensions

1ST
I don't know if I can even use a video to notify you guys about this bug but...

So I was watching a HermitCraft video (https://www.youtube.com/watch?v=tonM4xx88kU) and at 6:11, when one of the hermits killed the dragon, MumboJumbo heard the ender dragon death noise (and he wasnt even in the end dimension)