I see that this bug is a bit old, early February. But I am experiencing it now. I’m expecting that text I copy in preview mode will go to the clipboard in rich text. In reality, nothing is happening — nothing is copying at all.
I do see that if I don’t hit Cmd+A, but just use my mouse to highlight the text, then Cmd+C works.
Running Big Sur 11.2.2 on an M1 Mac. Obsidian v.0.12.1.