This is fixed in 6.0.0.066 which is currently only available as a pre-release.
You will need to upgrade all the plugin hosts and policy servers before removing the secondary policy server.
When unconfiguring the secondary, you should ensure that the pmserviced daemon is running on the primary.
After unconfiguring, you should do a pmsrvinfo on the primary to verify that secondary has been removed from the list.
A pmpluginloadcheck run on any host in your PM4Sudo environment should only connect to the active policy servers.
This needs to be run on every client system that is seeing this issue.1. Stop the pmpluginloadcheck daemon by running the following: