I have the exact problem when I turn on the bathroom fan also. I believe what I'm going to do is this summer replace the antenna with a better shielded unit and place the IRV on a different power circuit and see what happens. If you come up with a fix let the forum know.
Jake my sidekick (yellow Lab) 10/04 - 05/20
2017 RAM 2500 CC 4X4 Cummins Diesel
2016 Flagstaff 26 FKWS
AF&AM & El Korah Shrine of Idaho