[2.1] Crashing on the 21st

I have repeated crashes on the 21st of any Month, It sometimes goes through without crashing but will crash again after 1-2 months, always on the 21st. tried re-installing the game, the mod, fiddled with the negative modifier mentioned in other ctd threads.


This is the save file, should crash in a few days when it reaches 21st of 4th moon, if not let it run for a few more months.

www.mediafire.com/file/17rot0qnjli0y4s/The_Iron_Throne8289_04_02.ck2/file