On an avatar which has Viseme Parameter driven animations to my material that change a lighting pattern according to what phoneme I'm saying, these animations are no longer driven correctly on the current open beta (Build 1830).

This doesn't affect the normal mouth blendshapes setup and defined in the avatar descriptor. This behaviour is also only local, friends report seeing animations displaying normally (but I don't know if they were on the beta or not, so maybe it was just because they weren't on the beta).

Attached is demo with the first half of the video showing expected correct behaviour on the stable current build and second half showing behaviour on the open beta. (No audio was recorded in the video but you can see my HUD mic lighting up in first person and my mouth opening as I am speaking.)

Avatar shown in example (private) is: avtr_69db88d0-7898-4c91-9b9b-f3015a8df65d

Turn on Expressions > 'Switch Modes' to switch to the robotic texture and turn off Expressions > Clothing > 'Jacket On' to hide the jacket that is on by default.