copying a multi-master node to a standalone node

I am trying to create a duplicate of a production node that is in a multi-master replication setup to a standalone node for testing purposes. However whenever I try to make any changes to the testing database, I get the "shadow context; no update referral" error.

I have removed all olcServerID attributes, set olcMirrorMode to false, removed the syncprov module and its overlay entries, and removed the olcSyncrepl attributes. But after all this its still giving the error. What am I missing here?