Google's Pixel 2 XL flagship seems to be suffering from a very severe lag problem, but cases are not widespread. The bug hit Android Police and APKMirror founder Artem Russakovskii and popular tech YouTuber Marques Brownlee, garnering some measure of attention over the last several days. Google is looking into the problem and has reportedly found three possible causes, one of which warrants device replacement. This was the case for Russakovskii, who had his unit looked over by a Google engineer. After puzzling over the problem for two hours, the Google employee simply handed him a new unit and said that they would investigate the matter further.
The mysterious issue is a far cry for the everyday lag that happens to most Android devices over time. A phone that used to open apps instantly may take half a second or even a full second in extreme cases, a few seconds at most with extremely low-end devices or older flagships; that's all perfectly normal. Russakovskii's Pixel 2 XL, meanwhile, took a full eight seconds just to open up the camera in a video he posted to Twitter earlier this month. Brownlee was experiencing issues with things like apps opening slowly or certain animations being laggy and jerky. While Google hasn't publicly released any information on what causes the problems just yet, one thing is very clear; this is not your everyday Android lag, and if you have this issue, you'll know it. Your best course of action is to contact Google for an RMA. Since the company hasn't released any information publicly and its device support forum for the Pixel 2 XL doesn't seem to contain any solutions, all owners can really do for now is let Google handle it.
Since this is a hardware flaw in at least one of the three cases reportedly identified by Google, trying software-side fixes such as doing a factory reset or flashing a custom ROM may or may not work. As a precaution, the best thing to do, so long as you haven't voided your warranty, is to send the phone back to Google, rather than risk making things worse and excluding your device from replacement eligibility. This is also not the first time that Pixel 2 XL owners have had to deal with some serious issues, and it may well not be the last.