Yes, I've constantly had that problem (space not working) ever since we switched to the new editor, over a year ago. Maybe 2 years now?
It gets fixed for me if I hit enter to create a new row, but often times I've already typed out a sentence or two without looking at the screen. And have to re-write it all over again. This issue persisted for me on both Chrome and Firefox.
It doesn't always happen though, and I still don't know exactly what triggers it.