Chances are the HDMI switch is fine. HDMI components can get "confused" during the handshake process. This can be caused by a number of things, firmware versions of the display and or signal source device, loose cable, poor quality cable, power on sequence.
In my furniture store I generally have 15 - 18 tvs hooked to two cascaded high end HDMI switches serving audio and video from a single source. All can be running and you can power off and power on one tv in the mix and several others will go blank for a few seconds while they renegotiate their connection to the switch and source. Others keep playing like nothing has happened. I'll have the same thing happen occasionally in my coach when I switch sources. If I power up the Blu-ray player and then quickly switch from watching the Apple TV, the tv picture will occasionally get squirrelly because the handshake process was interrupted.
2014 SportsCoach 361BH - XCS Chassis, ISB 300 - 6.7 Onan QD 6000 Generator, Magnum MS 2000 Inverter