"overlay XXXX" is a database specific directive, i.e., it is not allowed globally. See slapd.conf(5).
Overlays can be used globally, unless a specific overlay implementation is designed to disallow this feature. Usually, slapo-rwm(5) and slapd-meta(5) do not work well together, since slapd-meta(5) provides built-in rewrite capabilities. The issue is definitely worth debugging. I suggest an ITS be filed.
slapd.overlays(5) also doesn't note which are global vs db only.
--Quanah
--
Quanah Gibson-Mount Principal Software Engineer Zimbra, Inc -------------------- Zimbra :: the leader in open source messaging and collaboration