It seems that I’ve found a solution for this problem and also for another issue with my calendar (see Calendar app partially in German)
I applied this tip and so far it seems to be the solution to both of my problems.
Now I can switch my locale without crashing the game and also the calendar app stays in the selected locale (which wasn’t the case before).
Be aware that it takes several hours before the process is finished.
Let me know if this solution also works for you.