UltraStudio Recorder 3G locks up Canon EOS R10 & R7 cameras

I have a BlackMagic UltraStudio Recorder 3G and use it to grab the HDMI output of Canon EOS cameras. I need to capture stills of the camera menus and this is a good solution for me. I've been using the UltraStudio Recorder for this purpose for some years. Previously I had a BlackMagic Intensity Extreme that did the same function for me, but it won't work anymore as its thunderbolt 2.

When you connect the UltraStudio to the HDMI of a Canon EOS R10 or EOS R7 camera and power on the camera, the camera locks up. No buttons work, LCD screen dead, power switch not working, can't do anything with the camera. The only way to recover the camera is disconnect the HDMI from the UltraStudio, remove the camera battery and reinsert it a few seconds later. This behaviour happens with both cameras and I have tried two different EOS R7 and two different EOS R10 cameras. The is no problem with EOS R6, EOS R5, EOS R8 and EOS R50 cameras.

I did find a workaround that let me grab the menu screens I needed. I connected the camera to an ATEM Mini Pro, and fed the program output in to the UltraStudio Recorder and that worked fine.

I'm using an M1 Mac Mini with Monterey and have tried all the recent versions of Desktop video.

Today I have an update on this... it now works fine

I'm still using the same UltraStudio Recorder 3G, with media express version 3.8.1 and the EOS R10 camera now has firmware 1.3.0. Randomly I just tried to see if it works and it does just perfectly. I hadn't thought to try as I'd been using the workaround for months with putting the camera in to the ATEM Mini then the output of the ATEM in to the UltraStudio.