Canon 5D mark IV-busy

I’m on the trial version, Mac OS Big Sur 11.6, testing two camera setup: Canon 5dM3 and 5dM4 to trigger at the same time. M3 works fine, 5dM4 is busy after every trigger and must be shut down and battery removed to reset it. I did try disconnect/connect in the Smart Shooter 4 software and that works but of course I don’t want to have to do that between each frame. I’m using a tether tools USB-C to cameras USB connection. Any ideas?

Crazy note: Tested with a regular old cheap USB-C to camera USB connection (not the really nice orange tether tools one) and it works fine. Go figure.