Have you noticed that it takes just a bit longer to unlock your Pixel 2 XL when you use the fingerprint reader? If so, you aren't alone. In the last few weeks since the update, there have been multiple reports that the Pixel 2 XL takes about a second longer to unlock the device when using the fingerprint reader. The good news is that Google is looking into it.
Fingerprint unlock in slow motion on Android 8.1 (left) and 8.0 (right)
Thankfully it isn't a very severe problem, as the only disadvantage is the extra bit of time it takes to use your phone, but compared to the nearly-instantaneous unlocking the Pixel 2 XL previously had, it is a bit unfortunate.
Reports are somewhat low-volume compared to other issues we've seen, but between our own accounts here at Android Police and reports made on Google's Product Forums and reddit, it's reasonably widespread. We can't verify if every Pixel 2 XL updated to 8.1 is affected. It could be that this is a universal problem and most people just haven't noticed, but it is just as possible that only some of us are experiencing the issue.
Google seems to be convinced that it's a thing, too. One statement by a top contributor says that "the team is aware of this and are looking into it," and the well-known and often-cited community manager Orrin has been reaching out to specific individuals in the associated thread for additional information and bug reports. Now that the issue has Google's attention, we probably won't have long to wait before it gets resolved.