Not entirely sure how to describe this in words which is why I put a question mark in the title, but it seems that the neck/head bones have some kind of weight painting influence on the chest bone or something. Here's a video to best describe what I'm talking about:

In the open beta, my scarf on this model, which is weight painted to the chest, seems to move/stretch a little when I move my head around. On live, this is not an issue and my scarf stays completely still. It's unfortunately not the greatest video, my recording software didn't really capture my full VR view, but you can definitely see when I'm moving my head side to side that the scarf moves and stretches in open beta, but stays still in live. I also have an avatar that has a necklace on, that in live stays still and resting on my chest when I look downwards on the chest, but on open beta clips into my chest when I look down. I didn't record that model, but if need be I can also provide that.