I have also never used a Before adventure script, so whatever the issue is, it isn't that. I understand closing the bug if you can't reproduce it, though. The next time I encounter it, I'll try to capture the mafia log surrounding it for further documentation.
I have also had this happen. I was using build 12868. I was in a HC run, KOLHS, and it was not happening right after logging in or changing gear.
It sometimes happened right after visiting the Florist Friar's, but when I stopped doing that, it would do it between combats with no other...