I set up a new (Huawei) phone for my wife and tried to sync her contacts (cloned from previous Samsung phone) with the Baikal CardDAV app running on a Synology diskstation and using CardDAVsync on Android.
An unexpected result was finding that Cardbook on my computer and “Provider for CalDAV and CardDAV” couldn’t make independent updates to the same record. That is to say, each others’ changes weren’t synced. She didn’t see my changes and vice versa.
Is there a solution for this, besides using the same client?
I don’t know “Provider for CalDAV and CardDAV” – I am very happy using DAVx5 on my Android phone, works perfectly.
I suspect your Baikal server having issues. Have you tried the native CardDAV App on your Synology?
And then, how did you import? I would try to import the contacts from the old phone right into Cardbook, and then sync. It will also show you more clearly whether your import has been successul, i.e. all fields have the right content. Maybe create a fresh addressbook for this excercise.
The problem arises only from using two different clients. You may be right about Baikal, though I’ve had no issue for years. I will look at both the Synology app and at upgrading Baikal (from 0.46, stable for years).