Use the fail-tasks command of the cell management tool on one Cell in the cluster after shutting down the Cloud Director service on all Cells to attempt to reset the activities including the NsxTVmTaggingJob activity.
Details on how to use the fail-tasks command are outlined in the Cloud Director documentation here, Update the Failure Status of a Task in VMware Cloud Director.
The Cloud Director service can be started again on the Cells after running the command.
If issues persist with after taking these steps please open a Support Request with VMware Support.