https://bugs.openldap.org/show_bug.cgi?id=9725
--- Comment #3 from Ondřej Kuzník ondra@mistotebe.net --- Getting the two OIDs to match is not enough, it does fix olcLastBindPrecision on the overlay's config entry but slapd.conf will keep ignoring it (it is a DB level keyword and so it never hits the overlay).
We could rename the slapd keyword in core, that would break slapd.conf for those that have migrated to 2.6.0 already, maybe that's something we need to accept?
I thought bconfig should pick the most specific keyword that matched (preferring overlay's version to database/global ones) but that's not a change we can make any time soon, if ever.