What kind of monitor failure is this? It turned almost completely white and noisy but gets somewhat normal after being on for a while

I bought a big 32″ IPS monitor for home use just less than a week ago, and it worked perfectly fine, until suddenly after I returned from a break, it turned on and the screen was almost entirely white. I’ve already contacted warranty department and they said it’s most likely some kind of backlighting or motherboard issue and not worth investigating, they’ll just replace it. But I’m interested in learning more about it because this is the first time I see something like this, and after looking up images of possibly similar malfunctions, none are quite like this, and none of the descriptions match my case.

Below are some images with a working Acer G246HL 24″ TN monitor for comparison with the malfunctioning Acer EB321HQU 32″ IPS:

Both monitors for comparison with test patterns

Good monitor’s test image vs Bad monitor’s test image.

As you can see, the image on the left is inverted and very bright. Also, it has these noticeable rounded corners which blend into expected colors.

Closeup of bottom right corner at different lighting. If you zoom in, you can see there is a weird 2-pixel vertical bars noise checkerboard pattern.

To show it’s not bad graphics card signal or cable, here are the On-Screen Displays of both Acer monitors (slightly different coz different models): Good OSD vs Bad OSD. And again, you can see the weird checkerboard pattern.

After a while it becomes sorta normal with visible noise moving around, and slightly visible checkerboard pattern: (bad monitor after a while)

And the OSD becomes more normal (bad monitor’s OSD after a while), although it never gets completely perfect and without noise. Corners are still very visibly different from the rest of the image.

At worst “whiteness” it also flickers slightly noticeably, but it goes down as it normalizes over time. If left turned off, it becomes white again after about 10-15 minutes and starts flickering again.

Is it the shape of the backlighting, rectangular with rounded corners that is causing this inverted noisy “bokeh” overbrighted effect? Or is it some software which is supposed to protect IPS panel from burn-in malfunctioning? Or is it a heating issue, since the power unit is situated inside the monitor this time around, and it consumes more power than the smaller one whose power supply is external?