When I was working in Kinetic hanna helped me get my filters working. I was trying to filter on blanks and used this syntax:
'{TransView.myPartNum}' !== 'undefined' && '{TransView.myPartNum}' !==''
Data Entry Form in Kinetic - Kinetic 202X - Epicor User Help Forum (epiusers.help)
Based on this I would suggest you verify the location of the single quotes, and then verify the name of the UD03PartNum field in your transview. It might actually be UD06_PartNum.
Good luck!