in December I purchased a 2013 CVO RG. I am experiencing the same thing. It is very annoying!! A few weeks ago as I was riding getting miles built up (currently I have under 500 miles on the bike) I also noticed the bike bike backfired a few times (sounded like a carburetor backfire.. weird). I was close to my HD dealer so I stopped in and had a tech take it for a test ride, the Tech noticed the "lag in throttle response, it is did back fire for him and he actually killed it pulling out of the parking lot. The service writer sent a report to HD. I received a call yesterday from my dealer ship letting me know HD got back to them on this issue and stated that they have several reports of the same issue, so when my bike is in the shop for the 1,000 mile oil change and check up to test ride it and run diagnostics and send a report to HD. SO... HD recognizes this problem but has no fix for it!!

This is very disappointing. I purchased a 35k bike and now have to spend about $1,500 on aftermarket pipes, tuner, throttle pak and dyno tune to make it run correctly... Maybe HD will at least split the cost with me to make it run correctly. WISHFUL THINKING!!
Bottom line is that this problem does exist. Harley recognizes the issue and has no fix for it..