Yeah, it's hard to know if the couplers or keystones are causing any sort of interference. I did purchase these couplers to try out, and it didn't help. I'm also using these keystones, which didn't help either. Now, one thing I'm wondering is if it was a mistake to trust a refurbished cable. My 15-foot Series-1 cable was sold as refurbished by BJC, which made it a bit easier to swallow its expensive price tag. However, I'm sure we've all had some refurbished goods in the past that weren't as good as they said. I know that this 15-foot cable can support Enhanced mode all by itself, but while you might expect it to work with an extra 5 feet of lesser-yet-still-premium cables, it doesn't. I did purchase a few active HDMI cables, but I don't know how restrictive they are to being run to a keystone on the source side. I'm assuming that I'll have to put the brush wall plate that you mention in on the receiver side if I decide to go with the active HDMI cable. I can always test it outside of the wall to see what restrictions I have. I ordered three Monoprice models to see how they work. One of them may end up being used elsewhere if it seems to work as those active cables are hard to find in shorter lengths, and my second spot will require a longer cable anyway. (I think I got 1 25-foot, 1 30-foot and 1 15-foot.) Anyway, I feel like I'm turning myself into a cable tester with all the cables that I'm trying out. Do you mean does the audio work fine if the video works fine? I can try it out when I get another cable. It is very weird though since it isn't the receiver adjusting the volume as the volume never changes. Just off an initial guess, I'd lean toward it being a firmware bug or something... especially since it only seems to fix itself when the unit is put into standby.