Isn’t this another sync issue that most likely will be fixed with the new Anysync protocol like you replied to my post @sambouwer ?
When I read this post it feels very simular to my experience where sync has some issues (maybe because of a firewall?) and then items, pages and texts don’t get synced properly. Only to later show up again (creating duplicates or just re-appearing again).
For my experience it’s never really lost data, only slow to sync. All my “lost” data has always shown up at some point. Though that point could be months and a few updates later which isn’t that ideal. 