When disconnecting from a server, or unloading chunks, Jukeboxes exhibit strange behavior. When a jukebox is out of hearing range and is automatically fed a disc by a hopper, it will begin to play the disc and emit particles, but will not make any noise. Jukeboxes also appear to not emit a redstone signal when out of hearing range/in lazy chunks. This makes the new 1.19.4 features adding hopper functionality to jukeboxes completely useless if you want to have automatic music players, as any redstone-based machine will break when a player disconnects or walks far enough away.