With both of my PX-716A have problems in every USB enclosure I own - 2x unbranded ALi-based, Freecom, LG & Lite-On. The only ones I haven’t tried are my PX-755UF & DRX-810UL (too valuable to open up).
They can write CD-R, but the beginning always fails verification. And with DVDÂ±R it always fails to complete the lead-out. (No problems when drives connected to IDE controller.)
If you do not work only in your pocket USB is problme is rather the only inconsistency in cooperation with the PX-716 …