Odd radar returns may be explained partly by the atmospheric ducting of the signal. Google "radar ducting". Have experienced the phenomena with VHF, listening to someone, a hundred miles away with a 6,000' range of mountains between us, transmitting a taxiing call while I was sitting in an office with a radio connected to a wire coat hangar as an antenna. Ships have reported picking up returns of coastlines 2,000 miles distant. Army instructors told of listening to PRC-25 (a VHF-FM set) transmissions made in Vietnam and being received 4,000 miles away in Australia. I don't know whether attack aircraft ever used the procedure, but it has been written the nature of ducting on a particular day could be predicted and the aircraft could make use of the duct (by avoidance) to close with the target to a much closer range than could be expected. Same principal the submariners use to avoid sonar by knowing where the duct, if any, is located.
Electronic Warfare and Radar Systems Engineering Handbook - RF Atmospheric Absorption / Ducting - RF Cafe
https://www.ibiblio.org/hyperwar/USN...RADTWOA-2.html
https://www.ibiblio.org/hyperwar/USN...H-P-08-04.html