Seems like the fault is 100% with the Denon - its entire reason to exist is to /improve/ your life connecting your AV sources and outputs, and if it is happy to certify the cable, and then fails to pass through the necessary signals, there is only one thing left to blame.
Dumb question - have you updated the Denon's firmware? I just got a 2nd-hand Yamaha Natural Sound AV amp with network capabilities and am having fun attempting to hack it to unlock higher model features. Started with a firmware update... something my glorious old Sherwood Pro-logic 5.1 monster never had...