h.b.furuseth@usit.uio.no writes:

This looks like a bug to me. objectClass has EQUALITY matching rule objectIdentifierMatch, which does not follow the object class inheritance chain. (...)

What makes slapd work is that it also disobeys RFC 4512 section 3.3:

Oops, I meant the opposite: It's 1st bug which slapd with 2nd bug work.