Sometimes you get lucky and see the activity light glowing all the time, or fading in and out intermittently. Sometimes you just won't catch it. Some devices may only put out interference when they are receiving commands. It can be random.

The bottom line is, move the antenna to a different spot. Some systems where I am getting interference problems, where I may be using the remote only 15 or 20 feet away from the antenna, I just fold the antenna down all the way to reduce interference. In days gone by, some removed the antenna, as the remote puts out plenty of RF for close in use.

Move that RFX around and retry.