In build 791, the apparent position of a user's voice when speaking fails to track their head position, instead it seems to come from a point a little beneath their nametag. I only experienced this bug from a user using FBT (and me also using FBT, they experienced the same bug with my voice). it may still work using 3-point tracking. Voice still follows in the XZ plane, just not vertically.
Steps to reproduce:
1. Find somebody using FBT.
2. Ask them to crouch or lay down, or use playspace mover to move vertically up or down.
Their voice sounds like it comes from their avatar's head position.
Their voice comes from their head position as if they were standing upright regardless of where their avatar's head is.