Just continue the old savegame then? Its not like you are missing out plot when being at the same moment of the game? Don’t know what your problem is?
The problem was that another old save file crashed so something was changed around since that version. That's why I even started a new save file to begin with. Old Save files can be pretty fucky. But deleting the old saves and persistent file fixed it.
I also encountered other errors, like the old save file skipping some animated scenes randomly so using old saves is a bad idea if I don't want to miss stuff for no reason.