Hoppers and droppers can put any item into a jukebox, even if that item isn't a record. As long as the jukebox is empty, or already contains that item hoppers and droppers are able to put (more of) that item in the jukebox.
Tapping the jukebox will make the it pop 1 of that item out and become empty again, regardless of how many items have been put in already.
Any item that isn't a record shouldn't be able to go into a jukebox.
This bug has been reported to our internal bug tracker for further testing and a fix. It is scheduled to be fixed in one of the future updates (no specific date can be provided).