Contacts sync not working on some Android Oreo devices
For the time being, the only devices affected are those running Android Oreo, including the Pixel 2, Pixel 2 XL, Nexus 5X, Nexus 6P, Pixel and Pixel XL. Most of those affected by the issue claim it started after they updated to Android 8.1 Oreo, but rolling back to Android 8.0 Oreo does not seem to fix it.
There's one workaround that seems to get rid of the problem, but it doesn't work for everyone. Apparently, clearing app data for Contacts on Android allows it to correctly sync, but, as mentioned earlier, it doesn't work for everyone.
It's important to note that not all Android Oreo devices are affected by the issue and it's hard to tell which are affected since Google hasn't found the cause of it yet.