According to multiple users on Reddit, the Pixel and Pixel XL's camera can have some serious auto-focus issues if you're using a certain type of case with Google's new flagships. When the problem occurs, your camera app will refuse to settle on a focus point, making almost everything in the frame blurry. Redditor HeshoMike uploaded a video of the phenomenon, and you can see it in action here:
The case that seems to be having the most problems with auto-focus is the Spigen Rugged Armor—though similar cases can cause the same issue. Ultimately, the problem seems to stem from dust accumulating in the sensor cutout on the back of some cases, which effectively blocks the Pixel's laser auto-focus system and prevents it from finding a focus point.
If you're experiencing this issue, you should be able to fix things up by taking your phone out of the case, cleaning the sensor area on the back, then putting the case back on. If you make a habit of wiping this area with your shirt every now and then, the auto-focus issue should be a thing of the past.
Speculating as to why the Spigen Rugged Armor case seems to be causing this issue more frequently than other cases (even the Spigen Liquid Crystal case looks to be unaffected), users have suggested that the Rugged Armor's rear sensor cutout is rather small, which makes it easy for dust to accumulate on top of the auto-focus sensor. Comparing Spigen's Rugged Armor case to their own Liquid Crystal offering, it does seem as though the sensor cutout is smaller on the former:
We asked Spigen if they had any plans on addressing the problem with their Rugged Armor line, but the case maker said they hadn't heard many user complaints about this issue yet:
We strive to provide the best service possible, with the highest regard to quality. We have not received many concerns regarding this issue for our Rugged Armor case from customers. We definitely appreciate it when our customers reach out to us regarding any questions or concerns with our products. Customer satisfaction is a top priority of ours and we hope to always deliver great products and service!
So far, there's only been a handful of users reporting this issue on Reddit. However, most of the Spigen Rugged Armor users who reported in did note some issues with auto-focus, so the situation is still developing.
It's definitely worth noting that Spigen has an excellent customer service track record, so if you're suffering from these auto-focus issues, you may want to contact their support team to let them know you're among those affected.