It seems to bomb when you hit the Professor being kidnapped queue.
I noticed that when I removed myself from the Beta stream, went back to the stock version, tried again the recent save, dodged the "you're trying to use a save from a higher version message, an in-game message came up, reporting to return to the camp, the Prof was taken after an attack.
So, Epi's suspicion about the odd value for that programmed event may be true, and it has not filtered down to the normal, stock version, only the Beta tract.