In my case, it was a bug with some mods - presumably Character Reload. I had to reinstall the whole game, get rid of Vortex and install mods one by one without CR.
I'll try it, but it'll take some time - after a bit of digging I managed to make the battles work but now the game crashes as I described in my previous thread... Nonetheless, I decided to reinstall the whole game before doing anything else.
Thank you very much, that has solved my issue! It seems I should have reinstalled the game long ago (I had installed back in patch 1.4.3, but first played on 1.5.0 - as far as I remember). I also moved it to the location on SSD (used to be on HDD). Now the game works as intended with and without mods (tested on new and old saves). Thank you again!
Well, I managed to reproduce the issue after deleting all mods (I had to use cheats to give myself influence and gold). However, it seems I have to try to reinstall the whole game... I'll inform you if it fixed the problem - but it will take a couple of weeks
I tried multiple times - everything is fine, according to Steam ...