Win10 or 11? As I wrote and your description of what happens to you confirms this, I never experienced similar problems with saving/loading and the GUI going wonky as you do. If it were a general bug, I would have it as well, but that is not the case. This seems to me a bug originating from a combined effect of win and ren´py versions and maybe some other python based program you have.
I'm on Windows 11, have been since it came out, late 2021. So, going back further then when the problem first appeared. It could be a combined effect, but one can't happen without the other. If there wasn't a mistake in 3Diddly's 'stuff' this probably wouldn't happen. If it did, it would have happened with people who are on Windows 10, or earlier versions. I think (not a 100% sure) I remember the people commenting they had the same issue, saying they were operating on Windows 10, 11 and also 8. And also one or two being on Android. So, based on that, my conclusion is that this is something that was caused by 3Diddly, and therefore needs to be fixed by him/her.
I could be drawing the wrong conclusion, I don't know. If I am, please (respectfully) let me know. I prefer to be wrong, and know why and how, instead getting into a figurative shouting match.
Also, if anyone has had the same issue I've described, please comment. I'd like to know how (or if at all) widespread this issue is. Thank you in advance to anyone who does.