SEPM 12.1.5 replication partners failure to replicate: "Unable to fetch data from remote site. Failed to generate BCP format file. Replication from remote site to local site finished Unsuccessfully.

After upgrading SEPM servers that are replication partners to 12.1.5, replication fails with the following error:

Unable to fetch data from remote site. Failed to generate BCP format file.
Replication from remote site to local site finished Unsuccessfully.
Failed to Submit

Some objects do get replicated eg. client groups and policies. But computers in a client group do not.

I have tried deleting and re-adding the replication partner on both sites, but still having same issue.