Appraisers have to chase down contradictions on MLS listings on comps because we do not have access to inspect the comps. However, there is access to inspect the subject, typically,- but in a hybrid, the appraiser is denied that access - instead, a random PDC person is sent to the subject property.
If the data on a comp is contradictory and can not be reconciled, the appraiser can choose to discard the comp and continue with the assignment. But if the data is bad on a PDC, then the appraiser can not continue. Either the assignment gets upgraded to a "traditional appraisal," or the order is cancelled? I assume it would be up to the client at that point.