Blender bug/s - "invalid commands"

“invalid commands”

Question. I have tried the different blender versions from 2.23 to 2.28 and noticed some inconsistencies. Not sure whether it’s my comp set up or blender itself.

I personally find blender 2.23 to be very stable. I do encounter problems using 2.28. I find the program will be working fine one moment and the next won’t let me scale or subdivide for no apparent reason until I exit out of the window and reopen it again. Any ideas why these “glitches” may occur?

Thanx.