does 'cn' have to be the same as in 'dn' ?

["Grzegorz Filip" <fliper_@poczta.onet.pl>]

hi
I'm using openldap-2.0.21 and I've noticed strange behaviour.
I've got entry

dn: cn=shelf,cn=case1,ou=netx,o=myorg,c=pl
objectClass: netxShelf
cn: shelf

and this is ok
but if i change 'cn' attribute like this

dn: cn=shelf,cn=case1,ou=netx,o=myorg,c=pl
objectClass: netxShelf
cn: other name

openldap doesnt want to accept it.
In prevoius version of openldap 2.0.23 it haven't any problems with it
I've searched slapd.conf to find any option responsible for that but i found
nothing.

thanks for any ideas
fliper