A friend and I were conducting some testing surrounding short range and long range radio and we both experienced this issue.

Short range radio default frequency is 38 Mhz.

Long range radio from picked up from arsenal default frequency is 48 Mhz.

If 1 user turns OFF the long range radio and the other user transmits over the long range radio, they will still receive the traffic if there short range radio is on despite the difference in frequency. (This also works vice versa if you speak over short wave and only have long radio on)

If both users switch the frequencies away from the default configuration then the radio's work as you would expect them to where you cannot hear the traffic when it's turned off.