https://bugs.openldap.org/show_bug.cgi?id=9888
--- Comment #13 from Vins Vilaplana vins@disce.org --- We've been able to hit this issue in our staging platform. We currently have an isolated server with this bug, so we're happy to run on it all kind of tests you need. Restarting slapd seems to fix the issue.
Additionally, we can also consider the option of starting a slapd with all debugs on (-d -1), take it out of service and play around modifying cn=config trying to trigger the bug. However, I'm not sure a -d -1 will include any debug regarding memory structures.