Some more findings:
- Groups of 50 contacts work more seems to fail but that is a tentative observation
- I have found a contact that was problematic for sync and it’s an aggregate with a complicated history, I have many such contacts and am currently unsure how to “detect” them based on the database itself.
The contact is from the Symbian days, when I would heavily use labels and I would put husbands and wives and kids of families in the same contact with different labels, after the move to SFOS the label information was lost and from time to time when I would often have to call multiple times to reach who I wanted to reach I started splitting those contacts and renaming them from family name to specific persons in those families.
The contact is part of an aggregate but the other part of the aggregate is not adjacent so not part of the sync attempt, I’ll now try to enable both/all parts of the aggregate to see what happens.