1 - Mine beeps very faintly if I shake my head quickly and the ANR is on.
2 - Mine also does something similar in one of the vans when transmitting on the Garmin 530 and the ANR is on. As the VHF aerials are above me I've always assumed that the RF shielding is not that great in the ANR microphone system. A fault with the antennae cables for the VHF radio could exacerbate this weakness.
I normally don't bother turning the ANR on in the vans (not that noisy) and save the batteries for the Beavers where the D50's are sensational.
W