Background music will play over top of records. Or, well, at the same time as, or to the side of...But background music is not cut off by records as it should be. Or, as it is assumed it should be. I don't know whether it's supposed to, but it didn't happen before.
Upon further searching, I found that the issue was marked "Works As Intended", regarding SMP, when it wasn't marked "Duplicate". I am not discussing multiplayer. I am discussing SSP.
Steps to Reproduce:
1. Place jukebox.
2. Insert record.
3. Wait for ambient music to pop.
Hm. I think this might overlap with MC-35856, in that both have problems where certain types of sound files are playing overtop of eachother.