[Q] Fire TV Stick switches to wrong HDMI on its own topic

When I first got the stick I connected it to HDMI-1 on my Panasonic Plasma to do some testing, I later permanently moved it to one of the HDMI ports on my Pioneer receiver. The receiver connects to the TV via HDMI-2 where ARC is. The problem is that when I switch the receiver to the Fire TV input the TV automatically gets switched to HDMI-1 where nothing is connected, this also happens when FireTV gets out of sleep mode. I have to switch the TV back to HDMI-2. I am assuming that the FireTV is doing this via CEC. I have a Chromecast, Roku, SageTV and a PC connected to the receiver and none of them exhibit this behavior.

I rebooted multiple times but id does not help. I can disable CEC on the TV or Receiver but then I loose ARC so that is not an option. Any ideas on how to fix this?