Unknown server id in contextCSN

Heya,

Currently running OpenLDAP 2.4.40 (most recent Centos patch) in a MirrorMaster environment.

The two instances have olcServerIds of 101 and 102..

Within the syncprepl, each server is using a RID of 999.

Everything appears to be working fine - but each of my providers now have replication cookies that seem to reference some other servers??

contextCSN: 20170918082017.961842Z#000000#*065*#000000 contextCSN: 20170915112957.845512Z#000000#*066*#000000

Is this an oddity/bug? Or could someone point me in the right direction to better understand what I'm seeing and where I've got confused?

Thanks in advance.