Ok, definitely not screen tearing.

Are you absolutely sure your monitor can support the screenmode that Mame is choosing? It looks a bit like an out of range signal. Some monitors will tell you that a mode is out of range on OSD or show black screen. Some won't, and display something very much like your screenshot. Many LCD monitors cannot display a low res screenmode and don't even attempt to scale it up. (The problem is less noticable on Windows and Linux because a. low res was rarely used even in 1995 on PC, and b. graphics card drivers on PC will generally scale up anyway.)

Don't worrry, I'm not trying to deny this is a bug. It almost certainly is. Just trying to narrow out some alternatives first that you would be able to fix at home.

[ Edited by KennyR 25.04.2019 - 20:30 ]