OpenLDAP 2.2.6 don't have this problem:
adding new entry "cn=test,dc=komi,dc=mts,dc=ru"
ldapadd: update failed: cn=test,dc=komi,dc=mts,dc=ru
ldap_add: Object class violation (65)
additional info: unrecognized objectClass 'abcd'
and
ldapadd: update failed: cn=test,dc=komi,dc=mts,dc=ru
ldap_add: Undefined attribute type (17)
additional info: x: attribute type undefined