Not sure if this is O-MR1 specific, but that's where I'm seeing this.

 Issue 810821  has been merged into this issue.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/a53dea68cae147d5fc9ecb2075feef448b248e78

commit a53dea68cae147d5fc9ecb2075feef448b248e78
Author: Michael Thiessen <mthiesse@chromium.org>
Date: Wed Mar 28 15:30:17 2018

VR: Fix issues with restoring System UI visibility.

On some devices, like the S8/9, System UI visibility is set by the
system before Chrome has a chance to check what system UI visibility it
should restore to when VR is exited.

Instead of trying to capture the state before entering VR and restoring
to that state, we should just unset the flags that we set for VR - none
of the flags we set for VR are normally used by Chrome outside of
fullscreen, which is the state we'll be in when leaving VR.

Some flags like the light navigation bar are simply cleared by the
platform when entering VR, so we need to set those again upon leaving
VR. As far as I know this behavior isn't specific to any device and
occurs on my Pixel 1 and 2 devices.

Bug:  810045 
Change-Id: If269df1e9bee56110f017c26f504b69db3003f52
Reviewed-on: https://chromium-review.googlesource.com/981414
Reviewed-by: Yash Malik <ymalik@chromium.org>
Reviewed-by: Yaron Friedman <yfriedman@chromium.org>
Reviewed-by: Theresa <twellington@chromium.org>
Commit-Queue: Michael Thiessen <mthiesse@chromium.org>
Cr-Commit-Position: refs/heads/master@{#546490}
[modify] https://crrev.com/a53dea68cae147d5fc9ecb2075feef448b248e78/chrome/android/java/src/org/chromium/chrome/browser/NavigationBarColorController.java
[modify] https://crrev.com/a53dea68cae147d5fc9ecb2075feef448b248e78/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellDelegate.java

Verified in build 67.0.3394.0 Canary build.  Looks good.