Solved
Dai suddenly crashing in combat
Not entirely sure what's going on but for some reason my game's started crashing in combat. In most instances the entire game closes, occasionally showing a black screen with the logo in the bottom c...
I have to apologies, I over-read a important line in your OP because I focused on the error message in your screenshot.
"you have lost your connection to the session" is in fact a problem that is related to certain fire spells like immolate or fire mine.
This is a strange bug that is very hard to pinpoint. Sometimes it happens and on another playthrough everything is fine.
If you already purged the affected save games best course of action is to not use fire magic.
