I'm running Windows 8.1, but the problem wasn't limited to a single project. It happened with every project I opened, and with a completely new project I created a s a test case. So it doesn't seem like a project-based problem.
I submitted a support case, though, so I'll discuss things with the support agent.
Using "undo/redo" in VScribe is a crap shoot; you never know what will happen. I've attempted to use it numerous in 3.0.6 with inconsistent results. I can be more specific if there is interest.
Undo and redo only affect resize and rotate actions and yes, it does not work consistently at the moment. We will be making improvements to undo and redo in future.