The game crashes without displaying any error message, and it happens at the same time each time.

I encountered an unpleasant situation (Steam version, modified with EWA), the game simply crashes without an error in the second mission of Necropolis; I hadn't observed this before (I've played the game with the mod several times, but this oddity only appeared now). What could be the possible reasons?

UPD

It should be clarified that the crash doesn't happen immediately, but after 10-13 turns.