Could be something to do with the "better skin" option in the main menu, but if you disabled it it shouldn't cause issues... What are your specs/version? Also, once v0.5 goes public, please share with me if the bug still happens for you, thanks! ♥
Sorry, just saw your comment! The next public version (v0.5.6) is planned for sometime between June and July, but I can’t give you an exact date just yet, game dev isn’t an exact science haha!