ERROR - An error occurred trying to connect the responsible parties for the imported objects. Reason: Can't find resource for bundle java.util.PropertyResourceBundle, key ResponsiblePartyHandler.InvalidSearchAttrib.txt
Then as per this usage note, and as I just verified locally, it is because the Responsibilities metadata is not imported. So if you set your flow properties as follows:
You will see that after export / import the metadata is gone:
The metadata therefore has to be manually added back following the import. In our case, we never use this field, and the ERROR has not caused any problems thus far (many '00s of flow deployments). Still, if anyone has any tips for avoiding the ERROR do please advise!