I was referring to this video:
He did stop at the position at one point. There were some really tiny movement here and there as well like shaking, but you can see that in a lot of rings routines at the elite level too. I don't think extremely tiny movements invalidate the hold unless the form deviates too much from perfect. What he did there is still a bit harder than holding a slightly high or low cross perfectly still for 2 seconds. Now I don't know much about judging in gymnastics, but perhaps you may be one of the very strict judges or there are FIG judges that are very lenient.
He did say it was his first cross from the title of the second video and that the title of this thread is about form check and he never implied that he mastered the cross or that he was strong in the cross. This thread should have been moved to the Digital Coaching section in my opinion.
I'm sorry to here about your injuries. Good luck on your training and recovery if they haven't already been all healed yet. Yeah, I can see that you were definitely not ready for cross back then if the back lever itself partially tore your biceps even if it was done cold. It sounds like your are a heavy guy with some muscular strength background in somewhere else before starting GST and straight arm work so it's definitely good that you are taking this slow and keeping your ego in check. 