If you have a bug that Rune's ending goes straight to main menu instead of initiating the porn scene, and you're on older saves, redo the playthrough from the Evening parts. During some of the choices there I added new variable a few builds ago, and it's used during the check of what Rune porn scenes are available to you.
In short, skip through the Evening/EarlyNight choices all the way back to that moment, and it should work.