Some of my contacts are not synced with iCloud

Hi there,

I do have 992 contacts on my iPhone 6s.

I turned on iCloud-Sync for contacts.

Using a Webbrowser I logged into icloud.com. There, only 980 contacts are shown.

Any idea what happened?

I already turned off icloud-sync, made sure, no contacts are left in icloud.com and turned on contact sync on my phone again - no changes.

Thanks,

Jochen