the game is putting stuff in your PCs memory till its 'full' and your game is stopp running because it does not overwright the old stuff.
this is happening very different for every users PC. This was 'introduced' with the last patch.
I personaly wondering why 1C deos not use the big benefit of STEAM and is releasing small patches with lesser fixes (not that there are none
). Sure, it would need that someone is working on these smaller things.
As examples
Bf110 canons
Ju88/Blenheim bombbaydoors
Ju88/BR20 compassystem
Gunnerhandling
even FM/DM/CEM fixes for several planes are still worked over i hope.....
This focus on the "mother of all patches" is propably not the best decission for their reputation IMHO