HDMI signal flickering on M1 macs.
I support multiple AV installations. We use Crestron HDMI to HDBaset transmitters to connect to some of the projectors. Recently, multiple users have come to us with Apple Silicon MacBook Pros that will not send video signal when they plug in to the systems. The screen on their laptop starts flickering on and of about once a second until it is unplugged. The machines behave like they are constantly being plugged and unplugged from an external display. I've tested all the cables and adapters (using the official Apple USB-c to HDMI adapters) on both Intel macs and windows PCs, they all work. Also the Apple Silicon Macs in question work when attached directly to a display.
Does anyone know what could be causing this?