I have the same issue with this post (Mikochi is appeared on a black screen)
[OS: Windows 11]

For my case:

1. Open from .exe file in the directory (outside bin folder) -> Working fine
2. Pin the opened app to the taskbar.
3. Close the app and open it again from the taskbar. -> The issue occurred.

No problem, I experimented a bit further and I figured out how to start it. I ran it as admin first because I saved it in my program files, then it worked normally. For the shortcut, the pixelart looks like this. But the one in the bin folder looks normal.