Actually I am seeing this too on Mac. It appears to be an anomaly involving trying to add the command button as a modifier for shortcuts, pressing command kicks it out of text enter mode in the window. Standby… i’m playin with it a bit.
I think I’m finding a bug. Edit>Invert Selection appears to be hardwired to command-shift-I. I does not appear as having a shortcut in the preferences window, although one is listed in the menu. If I try to change the shortcut for invert selection to something else ,sketchup 2020 crashes as soon as I use the new shortcut. Still investigating, @colin, can you replicate this?
New testing: I have successfully reset the Invert Selection shortcut to another key (letter b) and it is stable without crashing. However now both “b” and command-shift-I successfully execute a selection inversion. It’s as if that command function has two shortcuts. I am unable to add command key to any shortcuts as expected.