When the “exclusive” property of a ServiceTask element has been set to “true” this is not reflected in the exported BPMN xml
Other way around similar issue: When set to “false” in the BPMN xml (or when not present at all ) the “exclusive” property is marked as “true”. In the modeler.
When you import the bpmn.xml with “exclusive” set to “false” it is set to true in the modeler.
Also it is my experience that it is really needed to explicitly set “exclusive” to true in the bpmn.xml.
Otherwise it is not being picked up by the engine. Whether default or not.