I can confirm this nast bug. I also have errormessages like:

nouveau 0000:01:00.0: DRM: base-0: timeout

(a lot of them).
The X systenm becomnes very slow, and strange garph. effects occur. But after
seconds it stablizes again. It happens specially when moving windows.

I've got an arch system, but they don't seem to care there.

My system:

uname -a 

Linux ws-001 4.19.8-arch1-1-ARCH #1 SMP PREEMPT Sat Dec 8 13:49:11 UTC 2018
x86_64 GNU/Linux

I've got a dual monitor setup, with 

01:00.0 VGA compatible controller: NVIDIA Corporation GP107 [GeForce GTX 1050
Ti] (rev a1)

I think it's somewhere in the dri code is my intuition.
Stef Bon