I was testing out the demo of NG, and encountered what may be a major bug with how undo works. I was making some circles filled with gradients, and accidentally placed one in the wrong spot. When I tried to undo, however, that circle did not disappear, even when the others that were made before it did. After redoing, some of the ones on the bottom also changed appearance slightly.
Note that both screenshots were taken after having already undone and redone a couple times, so the circles on the bottom are messed up on the before and the after.
I still have the instance of Pro Motion where the bug occurred opened, so if you would like me to do anything that would help you with debugging, just let me know.