as I created a dav.domain.tld for OX addressbook/CardDAV sync to mobile clients I recognized in the mobile phone addressbooks that all telephone number entries in global addressbook have a leading “b” and single quoted numbers. E.g.: If the telephone number of an OX user is “+49-9876-54321” then the entry in the global addressbook is “b’+49-9876-54321’”. All users/entries have this issue, so I assume this problem exists from beginning. The CardDAV is not the problem, because also in the OX global addressbook all entries are wrong.
It seems to be a problem with the synchronization between LDAP => OX. The telephone number entries in LDAP are correct. Also a user change with modified number has the same result. Same with additional telephone/cell phone numbers.