ToME: the Tales of Maj'Eyal

Yes I am a serial offender here...
This time it was due to the Intimidating Cave spawning in High Peak 1. You can Rod of Recall out from in there.
This caused High Peak 1 to not get saved as well, so it was regenerated with more enemies and loots, and another Intimidating Cave which also regenerated.

I suspect I can loop this infinitely...

You can also go back and open up graves again and again too sometimes.

This could explain why the world map resets if you recall out of an ambush.