I was interested in this issue so I tested it out. Guillermo was correct in the functionality but you are correct that there should be an option in settings for Repeat and if not enabled it should stop at the end of the playlist.
I went back and tested Djay 2 and this works just the same as Djay Ai. Ie. It permanently loops around the playlist until you stop a track or turn off Automix. Interestingly enough, if you look at the Automix list you will see that as each new track is loaded to a deck it gets added back to the bottom of the Automix list, that’s why it never ends. (I called it Automix list so as to not confuse it with the “queue”).
The only work around at the moment (sloppy), is to clear the “queue”, add your playlist to the queue then Automix the queue. This will then play all the tracks and stop at the end.
Hope this helps
Ps. If you use the workaround method you can achieve the other functionality you wanted, which was going on to play another playlist after the first finished. You can add more than one playlist to the queue. Hopefully the Automix will be enhanced shortly to include more features.