This configuration should have been rejected by back-config just like it is rejected by slapd.conf. Patch to have this happen is at: ftp://ftp.openldap.org/incoming/Ondrej-Kuznik-20170825-ITS8637.patch

This doesn't reject online modifications just touching olcDBURI, but I think back ldap has no idea when it's configured as a slave to the chain overlay, so it can't do much.

--=20 Ond=C5=99ej Kuzn=C3=ADk Senior Software Engineer Symas Corporation http://www.symas.com Packaged, certified, and supported LDAP solutions powered by OpenLDAP