This bug was reported in open beta, but was not fixed before the beta got pushed to live:
As of build 785, custom walking animations for humanoid avatars no longer work fully. Any keyframe that isn't moving a humanoid bone isn't synced. For example, I have an avatar that turns off and on a couple of game objects every time I start moving. Locally, it still appears to work, but no one else see the game objects change state.
what other people see:
what I see: