Thanks for the feedback. I could've sworn I had checked following a restart of BigBox, but maybe not.
I just ran through it again by adding 2 more games to the playlist and saw they were in the playlist after closing and restarting the program.
There's a couple of odd behaviors with this aside from just that the games are not in the playlist. The other is that I enter via "All Games", but when I begin to exit back out of the game menus, BigBox thinks I'm inn my playlist.
Not sure if this is something the devs would like to look at, would be happy to help. Good news is it does look like it works, just not as expected.