It's been my experience that in many of these big games written in the nineties and early noughties, occasionally and for no apparent reason, a glitch develops in the savegame. I soon learnt to keep a backup save. I thought that was no more than our old friend Murphy up to his tricks again, but if something similar has happened to you in what might well be the same place, maybe there IS a tiny bug in the game.
So, advice to everyone, folks, take a back-up save before you enter Kriegspire!
Isn't it amazing how, after over 20 years playing, this game can STILL present us with something new?