Now it seems that ironically enough, the update has caused quite the opposite problem for other Pixel and Nexus owners. According to a post on the Pixel User Committee (via 9to5Google), some Pixel and Nexus owners are reporting that the update has actually ended up disabling mobile data for them.
This appears to be a bug of a so-called safety feature of the Oreo update, where the feature will actually block all mobile data on devices once the user has hit the data cap put in place by the carrier. The idea is that it will help to prevent overages for users, especially if they might be roaming.
The report claims that the feature is blocking all data without discrimination, despite the fact that some apps’ data being prorated by carriers, such as apps installed by carriers or communication apps like WhatsApp. The good news is that a Pixel Community Manager has since responded to the complaints by saying that Google is aware of the problem and are looking to fix it. For those who do not have a data cap, then your devices should not be affected by it.