I use the Spotify snap (188.8.131.521.gbe11e53b), minimised, and at irregular intervals, maybe every half hour, I switch back to find the entire window is blank white. The the XFCE titlebar is unchanged, and music keeps playing. The only way I can find to make it usable again is to start a new Spotify instance, which of course means stopping my music on the old instance, inconveniently. Media controls still function, but without being able to see the screen it's impractical to switch songs. The window certainly responds to inputs, but provides no visual feedback.
Dell Inspiron 13 5378 2-in-1
Manjaro Linux 19.0.2 Kyria (running Xfce 4.14)