UserAgent: Mozilla/5.0 (X11; CrOS x86_64 11151.59.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.94 Safari/537.36
Platform: 11151.59.0 (Official Build) stable-channel nocturne

Steps to reproduce the problem:
- Hook up an external display in "extended" mode
- Wait some indeterminate amount of time
- Get lucky and see it reproduce (a couple times a week for me)

What is the expected behavior?
Display stays in extended mode

What went wrong?
Display spontaneously switches to mirrored mode

Did this work before? N/A 

Chrome version: 71.0.3578.94  Channel: beta
OS Version: 11151.59.0
Flash Version: 

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