Make sure you have MOTS enabled, and that the last song is less than 15 minutes. One of the software upgrades allowed one to disable MOTS. Once disabled, it will pause at the end of a "playlist" (album or artist). Also, there is (maybe was) a limit to the length of a song that is cataloged by the MOTS algorithm. Any song longer than the limit will pause after playing. I seem to remember that this restriction was removed or relaxed, but I recently ran into the bs5 pausing after playing a long song so maybe it is still there.
Also, if this is a new machine or the last song was recently added, then it is possible that MOTS hasn't analyzed it yet. In this case, the problem will resolve itself.