The T-Pose is consistent with positions being randomly set to zero, just like the environment. I notice the color overlay is also impacted, which makes sense. Though it doesn't seem entirely random, there's a pattern behind this madness... Those values come from somewhere, but I don't know where yet.
It's very difficult to troubleshoot on my side without being able to reproduce it on any of the GPUs I have access to. But if you have a few minutes to spare, we can play a game on ping-pong where I send you a new version of the drawing module and you test it for me. I've uploaded a new version at the same link: https://drive.google.com/file/d/1JDK0C7XWdVYmRBNPWErXcoVtMRglyu17/view?usp=drive...
I would be very interested to know if this version works (though the framerate may not be good). Thanks for your help! ;)