Upgrade to VMware NSX for vSphere 6.2.4 to resolve the issue.
Symptoms:
An NSX distributed firewall rules policy cannot be published when a third-party partner solution is deleted from the Service Composer User Interface (UI). You see the error similar to:
Publishing of ruleset failed. Please see the tech support logs. The requested object: vm-xxx could not be found. Object identifiers are case sensitive.
Note: For additional symptoms and log entries, see the Additional information section.