The easiest way to reproduce: undoing a big action on multiple (many) files.
The problem is old, significant, and affects many. First time i wrote about it here, 4.5 years ago. I have had this phenomenon for 7-10 years.
What, if i sent you my config? I use a difficult lineup, it sure matters: 64 columns displayed (some of them with complicated calculations), 30 fields in the left panel. Or, may be, better variant: here are my columns.ini and usrfields.ini.heavy_config.zip (4.5 KB)