When I insert a disk into a jukebox, it starts playing, but when I use another jukebox next to it, the sound from the first jukebox stops (the particles are still there and the disk stays in the jukebox), and the second one starts playing. Basically, two jukeboxes cannot play music together.
How to reproduce:
Step 1: Place down a jukebox.
Step 2: Insert any music disk into the jukebox (eg. "c418 - blocks").
Step 3: Make sure you are close enough to the jukebox so you can hear it (within about 65 blocks of the jukebox).
Step 4: Place another jukebox down.
Step 5: Insert a disk into the second jukebox.
The first jukebox gets muted as the second one starts to play.
Both jukeboxes would play at the same time.
In Java Edition, both jukeboxes can play at the same time, these were my expected results.