Some Google Pixel phones have major camera issues
Unfortunately, it looks like a new issue affects some Pixel phones. A thread started in late October by a Pixel XL phone users mentions a major camera issue. Here is how he describes the problem:
Since the the thread was started in October, many Pixel owners reported their phones are affected by the same camera issue. Unfortunately, Google has stopped answering people's concerns, even though some continue to post stating their phone's camera app doesn't function properly.
Luckily, the community has made some progress investigating the issue and discovered that the problem only affects the international Pixel/Pixel XL versions.
It's worth noting that third-party camera apps do not solve the issue. Also, it appears that some of those who managed to get a replacement phone started to experience the same issue.
Google has yet to comment on the matter, though it does seem to be aware of the camera problems. It remains to be seen whether or not it will be able to reproduce it and find way to fix it.