Fedora 26 Kde Xorg, Nvidia proprietary drivers

When I go into full screen with the mpv video player, all desktop environment widgets like the task bar and system clock
(i.e. the default kde tray clock) reverts to some previous time, like a couple of days a go (it varies), then freezes in time and becomes unresponsive. The taskbar shows which programs were open at that time. Actual window contents (like web browser) are current, while anything related to the desktop environment (task bar, kde clock widget, kde rss reader) displays a state from the past.

When I quit fullscreen, the DE reverts back to current time and works as normal. 

mpv devs says bug is not theirs (https://github.com/mpv-player/mpv/issues/4786)