There’s an unusual message on the Physical Web forum announcing that Nearby Notifications will be temporarily removed from Google Play Services:
The outage will start in early October and end in late November as the next version of Google Play Services is rolled out
Physical Web will automatically be enabled via Chrome for Android on devices on which Nearby Notifications is suppressed.
This means that while notifications might still work, they will rely on Chrome’s Physical Web mechanism which previously wasn’t as reliable. Also, Settings… Google… Nearby discoveries won’t work.
It’s unfortunate this had to happen as it complicates what’s already a very complex setup for many people. If you have an important rollout then it might be best to delay until late November.