Comment 2 for bug 1720835

I can reproduce this with Ubuntu's package and with Debian's 0.27 package if I manually use "--vo=wayland". When using the wayland vo, all "window close" commands (like quit from the activities menu, alt-f4, etc) do nothing. You can still quit mpv by typing "q".

Possibly unrelated, but this major rewrite PR was recently submitted for wayland. It might be a good idea to see if that fixes this issue.
https://github.com/mpv-player/mpv/pull/4945