I think you can try this through the plmxml_export utility, you need to find the root element of the template. This should be an EPMTaskTemplate and see its UID using the Print Object view
plmxml_export -u=user -p=password -g=dba -xml_file = "your_path\test.xml" -transfermode = workflow_template_mode -uid="uid_wf_template"
Do you accurately export the process template, not the completed process? These are different objects. I tried and I do not have any extra objects except the objects of the process itself