Bug#971343: Animated background/wallpaper (changing over time) causes system freeze on Nouveau

[Leandro Cunha]

Analyzing at what point the problem was solved without the whole
system stopping, which occurred specifically with Wayland and not with
Xorg. It has a greater effect on use. I think it is more appropriate
to lower the severity to important.

https://www.debian.org/Bugs/Developer#severities