If you are noticing some records are not syncing, here are some common solutions:
Basic contact information is missing, such as name, email, and/or phone number.
If more than one contact in the List (in Church Community Builder) has the same email and phone data, they will be synchronized as one. For example, if you have a husband and wife sharing the same email or phone in CCB, then only one will be synced
If the contacts have the same email address but different phone numbers, they will be validated as duplicate contacts and only one contact will be synced.
Similarly, if the contacts have the same phone number but different email addresses, they will be validated as duplicate contacts and only one contact will be synced.
Anyone removed from the Group will remain off the Group even when you sync again.
You can also check out the sync failure logs inside of a group to see which records didn't pull over and why. Click on the Sync Failures tab to see each record that didn't sync.
If you need to add or edit data, do that on the CCB side; you can then do a manual sync ASAP or wait for the next sync.