One solution that works for me (most of the time) Blender. Set up BSDF SHADER with IMAGE TEXTURES. For Transparency set the Blend Mode to ALPHA HASHED in the MATERIAL PROPERTIES and lower the ALPHA value. Export the Szene as a GLTF2.0 WITHOUT COMPRESSION. Open the GLB in the REALITY CONVERTER. Check if everything looks good. If there is no transparency remove the MATERIAL and re-import it. Works for me. Export the model as a USDZ.

Same here. I create an animation in blender and export it as a gltf. Then I use the reality converter and everything shows up fine. I import the usdz into Reality Composer and it also looks fine. But when I export the Reality Composer USDZ the animation speed is messed up. Very frustrating.

I am looking more closely at the ARHumanBodyManager Skript and the following event: public event Action<ARHumanBodiesChangedEventArgs> humanBodiesChanged; The way I figure is - after a body is found the script should stop looking for new bodies. Only when the body is lost, should the script search for new ones.