Over the weekend, people with review units of the Pixel 2 XL began noticing a problem. No, not the already-known issues of muddy color and grainy textures when viewed in low-light, but one that’s potentially more worrisome: screen burn-in. First reported on Twitter by Android Central’s Alex Dobie, multiple people have noticed that when you look at the screen with a gray background, you can see faint outlines of the phone’s navigation buttons on the bottom.

You can see it below, and I can confirm I’m seeing something similar on my own review unit.

That's some pretty wild OLED burn-in on the Pixel 2 XL after maybe 7 days of full-time use pic.twitter.com/EPJTs6D0Kg — Alex Dobie (@alexdobie) October 22, 2017

Screen burn-in isn’t an uncommon issue, but it does seem especially worrisome that it’s showing up within a week or so of these units coming into usage. It’s also possible that what we’re looking at here is image retention instead of actual screen burn-in. If that’s the case, then it’s not as permanent. Neither one is good, but “ghosting” goes away where burn-in may not. Android Central has a good breakdown.

Whatever it is, it’s worrisome, so we reached out to Google for comment, and here’s the response from a spokesperson in full, but obviously pay attention to the second part more than the rosy specs listed in the first half:

The Pixel 2 XL screen has been designed with an advanced POLED technology, including QHD+ resolution, wide color gamut, and high contrast ratio for natural and beautiful colors and renderings. We put all of our products through extensive quality testing before launch and in the manufacturing of every unit. We are actively investigating this report.

If it really is genuine screen burn-in (and early indications do, in fact, seem to point in that direction), it’s a really big problem. Many screens, especially OLED screens, do begin to exhibit burn-in over time. But that time span is usually measured in multiple months or even years, not days or weeks.

We’ll be keeping an eye on the issue in the coming days and will update our review of the Pixel 2 XL as is appropriate. Having a portion of your screen permanently marred takes what was a negative point against the phone and turns it into something much closer to a deal-breaker.

Update: here’s a big, giant shot of the issue on my review unit Pixel 2 XL. As you can see, it’s faint — but it’s also not the sort of thing that should even be possible a week or so in.