erro ergo sum

At least for Belranga it was a bug. Can't tell if that's a pun or a genuine response. If the former, I'm amused. If the latter, I'm still amused, and also I have an archive save from right before the fight, so I'll update the game and try again.

I recently defeated Belranga on PotD (I believe on game version 4.0.1.0033 or 4.0.1.0034). When I left the Crystal Desert area afterwards, the location simply disappeared from the map. I've read elsewhere that megabosses are meant to respawn, so I'm wondering whether this is intended behavior or a bug?

I've encountered this on occasion. As far as I know, it's always meant to happen to characters who are knocked unconscious with three wounds. In particular, it also seems to happen when characters, including those with no preexisting wounds, die to raw damage (e.g., from Disintegration) or from some very specific instant death effects (happens with Belranga's Shattering Screech vs. petrified characters, and I think I've seen this happen due to a near-death character hit by a Wizard's Death Ring spell as well). I have no idea if any of this behavior is consistent or whether it's an intentional mechanic outside of characters dying with three extant wounds.