OEM Not Monitoring PDB databases

We are having an issue where no metrics are being loaded for PDB databases.

These are RAC containers and collection seems to stop during agent remastering

when one agent is taken down and the monitoring is shifted to another agent in the cluster.

After that we get no metrics in the repository or alerts on the PDB's

Not tablespace, response, nothing.

I have tried manual collections of the metrics

and using emcli to relocate the CDB back to the agent that was working.

But cannot get it to start loading short of deleting the target and readding it.

A PDB that was not loading started loading after the agent was upgraded to 13.3