ACLs using dynlist overlay

Dear collected list wisdom,

I'm trying to set up access control using membership in a dynamic list.I've activated the dynlist overlay and configured it like this:

olcDlAttrSet: groupOfURLs memberURL member

and installed an ACL:

olcAccess: to dn.regex=".+,<some base>" by self read by group/groupOfURLs/member="<group DN>" search

Browsing the directory I can see the member attributes being added to the group, but testing access with slapacl I encounter the following error:54ef3976 => bdb_entry_get: found entry: "<group DN>" 54ef3976 <= bdb_entry_get: failed to find attribute member

What am I doing wrong? N.B.: I _did_ add member to the list of allowed attributes for a groupOfURLs ...

TIA Ralf Mattes