The page does not sync because where it usually says ‘Synced’ it says ‘No Connection’. It seems to be for only one page in particular.
I was able to provide you a screen capture of the bug, here it is:
The page should sync and there should be a connection to the backup node.
OS Build: 19044.1889
Lenovo Thinkpad P50
The issue looks to be similar to this reported bug. Syncing to backup node stopped working