Hello! Could you provide the resolutions of your screens? We tested it on Linux cinnamon and the character was covered by the taskbar but was visible, try changing taskbar positions to top, and then back and let me know if the problem persists, I will test it again and try to replicate the issue.
The app behaves this way if it somehow started working in fullscreen mode instead of a borderless window, try to toggle fullscreen mode and let me know if it helped.