LDAP and bad mailaddress

we have a NAB for external addresses and it works fine for (objectclass=company) and (objectclass=person) .

There is one bad exception:

persons mailaddresses which are empty are presented like “firstname_lastname@OURDOMAIN.LOCAL”

We only use field mailaddress (Forwarding Address) which (in this case) is “”

Any idea? - Your help will be much appreciated