Google Chrome	70.0.3538.110 (Official Build) (64-bit)
Revision	ca97ba107095b2a88cf04f9135463301e685cbb0-refs/branch-heads/3538@{#1094}
Platform	11021.81.0 (Official Build) stable-channel chell
Firmware Version	Google_Chell.7820.315.2
ARC	5133027

From time to time, with no apparent input/cause, the following happens on my Chromebook:
1. The whole screen is grayed out / focus is taken away from whatever I was doing
2. A "Thank you for your feedback" appears in the center of the screen

I think this started around 2-3 weeks ago.

Please let me know if I can provide any extra information that might help debug this.