It means that you run it in a replicated environment at your own risk.
Unfortunately, there is no defined standard for the "memberOf"
functionality (it's a MS hack) and so there's nothing that details how it
should or shouldn't behave with replication.  In general, things work fine
as long as:

Does the same apply to the rfc2307bis schema which gives your the groupOfMembers objectclass?
Out of curiosity.

Thanks!