Zimbra 8.6 duplicated contacts

[mafiabusiness]

I have an account on my Zimbra 8.6-GA Server.

I have 300 unique contacts.
Today I found I have have 3800 contacts.
Turns out there is a random multiplication of contacts in there.
Some have 2, some have 20, one person there exist 398 copies of.
Totally random.

I have a Mac with Mac OS X 10.7.
I have an iPad with iOS 8.1
I have a Blackberry Password with BBOS 10.3.

They all use CardDAV.
Does anybody have any idea at all?

Miguel