There are changes in the new Rules of Golf in relation to caddies ........
Various changes in the new Rules will affect what caddies can and can’t do to assist players in 2019:
Under new Rule 10.2b(4) once the player begins taking a stance for their stroke, and until the stroke is made, the player’s caddie must not deliberately stand on or close to an extension of the line of play behind the ball for any reason, and
Under new Rule 14.1b, the player’s caddie will be allowed to mark and lift the player’s ball on the putting green any time the player is allowed to do so, without needing authorisation from the player.
You can read more about this and the reasons behind the changes on the England Golf website here