I have noticed a kind of annoying issue with Physbones that if an avatar has a toggle that updates the physics by turning the script on and off, whatever way you are oriented when the physbones are enabled becomes the new default point, so if you are laying on your back and turn the physbone off and back on again laying down is treated as the the falloff point where it will apply 0 gravity then if you stand up the bone is dragged down by gravity.