Sometimes (not always), I notice a glitch when Mortar / Devastator rockets explode. See screenshot below.
It doesn't last very long, probably only a few frames.
Setup: Xonotic 0.8.2 on ArchLinux, with nVidia 378.13 drivers.
Mario's tip: disabling r_coronas_occlusionquery is a workaround.
I have the same issue, only the bands are just vertical, not in a checker pattern.
Linux Mint 18.1 KDE5, Nvidia GTX 1060.
moved to darkplaces#114