Jim,
I have 2 857D's one an 07 build the other a 2010 build and have never run into the problem you are describing but for both to be doing the same thing would lead me to think it has to be something common, Question are you using and external tuner or antenna switch with the rig's if so could be something to do with that other than that I'd say you have an interesting problem and I will be more than interested in the finial solution to it.
Good luck
73's
troy
ke4ska?
