Just to echo Twistedmelon, I've been observing the same behavior in my MX-980 for a number of weeks now. Prior to that, RF signals from the MX-980 were transmitted without a substantial delay. Now I'm guessing there is a 500-700 ms delay between pressing a button, and the MRF-350 transmitting it. There is no interference observed on the unit.

I hadn't made any changes to my remote or updated CCP in probably close to a year. A couple of weeks ago I added a single button to one of my devices, and at the same time allowed CCP to update.

After I uploaded the changes, I observed the problem.

I tried again last night to switch everything to RF, and I still observe the problem.