I too am having issues with UDT discovery in a juniper environment
I've tested with the physical ports in the unmonitored state (via the web gui not the below SQL command) and I still loose data. Looks like I need to retain both physical and virtual ports so I can map UDT end points.
Maybe if solarwinds cant provide a quick solution a temporary doubling of our UDT ports licenses would provide a workaround for those aflicted with the Juniper UDT issue. (Hint Hint)
I'm running UDT 3.2.