Sounds like your mortgage processing system/LOS doesn't have any sort of pre-UCDP validation of the appraisal. If you havent already, you might double-check with them to make sure they don't have this pre-UCDP validation, as many LOS's/mortgage processing systems do have a solution in place.
If they don't, a few of the mortgage tech companies have developed quick, free, standalone "UAD checks" that validate the appraisal prior to your UCDP submission - to try and catch issues before submission. These solutions scan the appraisal automatically in seconds to make sure the appraisal file conforms to the UAD formatting that is required for electronic submissions to UCDP (non tech/nerd version: they make sure your appraisal is good to go without a person manually reviewing it). They aren't integrated into any mortgage processing systems or LOS tho.
a la mode has one called the UAD Reader, and Appraisal Firewall's AF Express does this as well. There may be others out there too.
If you have the appraisal file, you might try out one of these options to see if it helps. A possible workflow might be to 1) receive the completed appraisal in the mortgage processing system, 2) save it out to the local computer, 3) upload it to one of these UAD Validation options, 4) get the results, 5) deliver results to the appraiser if corrections are required, or if there are no issues, proceed with UCDP submission.
The only caveat is that these free solutions require the appraisal to be in an XML file format (they dont work with PDF appraisal files). So hopefully you can get your appraisal in XML. Most appraisers can deliver the appraisals in XML if you aren't getting those in that format today.
There are other solutions to eliminate the timely/manual review process but they might require more of a change to your entire appraisal process.
Sorry for the lenghty post. Hope this helps.
PS - "These pretzels are makin me thirsty!" :-)