So I've started a game as France on Tuesday (1.31.0) and played 15-20 years without huge problems. All DLCs bought and active, no mods whatsoever. On Wednesday I continued that savegame on patch 1.31.1, played another evening session without problems. Now I have invested about 11 hours of real-life and 41 years ingame time into that campaign, crushed England and Burgundy into oblivion, everything without coalitions so far, integrated all my French vassals, completed 10 missions, have upgraded my 2 monuments, have 90+ favours with Castile and am ready to put a Valois heir on their throne and then this happens today when I try to resume the savegame:
The world is empty, France and all other countries don't exist anymore, starting the game automatically ends the game immediately

Sorry for the screenshots being in German, but I think the problem should be clear.
Savegames attached in case anyone wants to look into this.
Anyone having similar problems?