sshd openpam errors in log after replication

[MikeyG]

On my backup system where my data gets replicated to, I keep getting these errors in the logs after every replication from my main system:

Apr 26 00:16:09 backupnas sshd[20644]: in openpam_check_error_code(): pam_sm_setcred(): unexpected return value 12
Apr 26 01:05:24 backupnas sshd[20642]: in openpam_check_error_code(): pam_sm_setcred(): unexpected return value 12

Anyone know what's going on? Replications do succeed.

Both are running 11.3-U2.
Replication tasks were set up SSH+Netcat.