On a multi-Playlist configuration - settings for the 2nd Playlist are not saved. This is shown by clicking the main Playlist1/2 tree icons and noticing the tick-boxes not matching up with Playlist1.
Only solution is to manually edit mairlist.ini
I’m afraid this is still occurring in v18:
Playlist 2 options re-appear when switching to the same view on Playlist 1. The Playlist 2 settings are not saved, either.
Already reported in the German forum. There were two or three other spots in the source code which I failed to check. Should be finally fixed in v2.1.19. sigh