I'd be suspicious of any research claiming that dihydroetorphine is non-addictive as such, especially in a patent application where they'll really be wanting to exaggerate the difference between the claimed drug and previous work in the field.
Animal studies show that DHE is self-administered which suggests some abuse potential. However it does seem to be less addictive than most opioids, and slower to develop tolerance too, and that coupled with its high potency make it unsurprising that the Chinese have adopted it as an analgesic and for opioid substitute treatment.
Sounds like an interesting drug at any rate, wonder how it compares to buprenorphine seeing as they're pretty closely related. DHE is a full agonist and much more potent than bupe, but if its less addictive and produces less tolerance than most mu full agonists there must be something special about it.