I have the blur effect disabled. When I run a fullscreen game in Steam, which disables compositing, and then exit the game, blur is reenabled even though the check box is still unchecked. To disable it, I have to check the box, apply changes, uncheck and apply changes.

I'm using KDE neon developer edition (stable), plasma 5.7.4, qt 5.7.0.

(Perhaps this is related but in the compositor settings I have UNchecked "suspend compositor for full screen windows", and yet compositing gets suspended.)