There are glitches in routines that just happen at times. There are areas of the map that heat up my computer. Some factions are worse on the hardware than others.

In my current Austrian campaign, Finland heats up my machine incredibly fast. Just hovering there on the map is enough to shoot up my temp to dangerous levels. With other factions it has been India or the Iberian peninsula. (or maybe it is the new patch)

Playing in Windows the saves are very slow and I even get white screens for a few seconds. The Russian AI turn usually does this too about mid way through.

I think mostly they are just leaks and glitches that have not been sorted out yet.