The undo function jumps back two instead of one step. This is no pleasure in the long run. Please fixt that.
I'm not 100% sure on this so I'll test it later, but do make sure that you don't have the text editor part open (in other words, make sure you're not clicked into anything in an element that's still editing text), or clicked into any of the Styles where it's focused inside one yet. That will actually "stop" the Undo from working until you click out of it.
What I don't know is if that undo is actually doing something or not when you're clicked into editing something yet. Seems that it's not doing anything, but it could be that it's doing something and mimics that it's jumping ahead or back.
I'm on a Mac, I have not personally seen this jumping ahead or back more than 1 step at a time.