Chrome Version: 65.0.3298.4
OS: Win 10
Graphics Card: Nvidia GeForce GTX 1080
Device: Oculus Rift

What steps will reproduce the problem?
(1) go to https://webvr.info/samples/03-vr-presentation.html
(2) click Enter VR button
(3) Put on headset
(4) move head around and pay particular attention to the green "fps" label.

What is the expected result? The fps label, and all of the content should be rendered clearly and not have any glitching or corruption.

What happens instead? with head movement, there is some glitches and artifacts particularly noticeable on the green fps label.