Usually, the vehicle after totally assembly in OEM plants goes to a yard, waiting to ship to the distributors. At this time, some problems found in the incoming parts/sub-assemblies supplied by the supplier, OEM is not sure there is the same problems in the vehicle that has been already assemblied and stored in the yard. So the vehicle in the yard cannot be shipped until re-inspected OK. In Chinese version of IATF 16949, it calls whole vehicle(in the yard) awaiting to be inspcted.
Stop ship is a more serious situation. OEM is sure that there is(are) problems in the vehicle that have been stored in the yard. So OEM make decision to stop the shipment. The malfunctional parts/sub-assembly of the vehicle need to be replaced.