That... Doesn't make sense. Why would you direct high-powered EM radiation at someone in order to receive soundwaves? The only thing EM radiation carries back with it when it bounces off something are its vector and energy (wavelength, intensity, frequency). As far as I know, there's no way to interpret a sound wave through EM radiation. It's hard enough to calibrate a RADAR to interpret the shape of an opaque, solid object. I also can't imagine a device which is accidentally emitting tremendous amounts of EM radiation at a specific target. Once a basic outstanding of the device is achieved it would be trivial to find out if one is used nearby, which doesn't make sense from an espionage perspective.
Interception requires "passive listening" devices like radio receivers or sound amplifiers, or infiltration, like "man in the middle" hacking attack.
lol I am just re-vomitting rumors I saw on Twitter so take it with a giant grain of salt