Particles are rendered incorrectly when you are in spectator mode and spectating another player in the first person view. They're rendered using the position/facing angle of the spot where you enter first person view, rather than where they actually are while spectating, which causes the particles to render incorrectly when the player moves around.
Particles are rendered incorrectly when you are in spectator mode and spectating another player in the first person view. They're rendered using the position/facing angle of the spot where you enter first person view, rather than where they actually are while spectating, which causes the particles to render incorrectly when the player moves around.
Video showing the issue here
edit: just wanted to clarify that this a suggestion for a vanilla bug to fix, not a bug that is caused by patcher.