HDMI capture dongle as "camera" for Facetime Issue

Until recently I was able to use an HDMI input as my "camera" for Facetime. Now, it looks fine when I'm setting up a call, but now as soon as the other party accepts the call, the screen (my camera feed which is my HDMI capture dongle) distorts and looks like old fashioned scrambled cable TV on both my screen and the other party's screen. Is this due to a software "upgrade"? IT USED TO WORK FINE. I'm using an iPad Pro.