I now have five computers set up to sync favorites on Canary 18.104.22.168.
After the move from 167 to 168, one of the computers informed me I needed to sign out and sign back in to resume sync. After I did that an old set of favorites appeared across the five computers.
When I started to remove the old set, I saw some odd behaviors.
First the sync seemed to be intermittent, in that some of the deletions would sync followed by a pause. This sync/pause cycle repeated a couple of time.s
Second, the Favorites page on one of the computers became completely unresponsive. None of my clicks triggered any action. Once I closed the tab and opened the favorites on a new tab, things proceeded normally.
@Elliot Kirk While I was expecting some time lag between the change on one computer and the next, I expected all the changes to occur at once on each computer. Instead on each computer some of the changes would be reflected, then a pause, and then some more (repeat).
I also did not expect the Favorites tab on the active computer to become unresponsive and have to be closed and reopened.
I also did not expect after responding to the sign-out/sign-in error message that old favorites, not previously in the list on that computer, would reappear across all the syncing computers.
I hope that is helpful and addresses the question. If not, please let me know.