Acer xb271hu - pixel brightness "shimmer" - defect or normal?

[sfhf]

When I turn on the monitor after it has been off for a while (1hr+) it has alternating levels of bright/dim in vertical bands. They disappear after the monitor has been on for some minutes (~5-10). The effect is more apparent at lower framerates (such as HotS being capped at 60 fps on title screen), but is still there at 144hz as well.

Example - initial "cold" turn on of monitor:
https://i.imgur.com/Avc4rnI.jpg
https://i.imgur.com/eulPOSm.jpg

After ~30 minutes:
https://i.imgur.com/VIqU3is.jpg
https://i.imgur.com/sETRICj.jpg


On the pixel inversion test (https://www.testufo.com/inversion) it shows to the eye as alternating light and dark horizontal lines on the moving pattern - evenly spaced but very different looking than when the display has been on for a while (or the still image).

If this is normal for the xb271hu (and/or pg279q, xg2703-gs) It is otherwise an excellent monitor. I am worried it may be a hint that a component failure is imminent though.

Any advice appreciated,
-sf

 

[sfhf]

Update on the pixel inversion test, using updated camera settings:

Cold start of monitor (not pc) with G-SYNC off, 144hz (easy to see the bands):
https://i.imgur.com/PZGaJwc.jpg

Looks like it takes ~20 minutes for the inversion test to look normal:
https://i.imgur.com/TX2V2hb.jpg

edit: added picture for normal.