In Contacts "Favorites" list depopulates unaccountably

[Android Central Question]

I have android version 8.0 on a Galaxy S7. I sync contacts with Microsoft office 360, which is up to date. I use the native contacts app on the phone. I have about 10 contacts that I have starred on the phone. periodically all or most of them become un-starred and I have to laboriously repeat the process. I do not have a clue what causes this to occur. There is no way to re-star a favorite other than by editing the contacts one by one. I have them in a group, but its still a hassle

I'd appreciate help avoiding the problem.