Has the law on how to take a penalty kick been changed?
2017 Law 21.4 "Sanction: Unless otherwise stated in Law any infringement by the kicker's team results in a scrum at the mark. The opposing team throw in the ball."
The current Law book uses the same criteria but gives no specific Sanction.
We were told there were no changes in the "simplified" rewrite, so is this an error or a change? Should we apply 9.7 (a) " A player must not intentionally infringe any law of the game" and award a Free Kick?
Locally referees often merely require a correct retake for the first offence.
Been a while since you submitted this question, but The Rugby Ref has only recently been able to get a definitive answer.
You are correct in saying that match officials were told there were no changes in law when the law book was "rewritten" for clarity. However we have to be pragmatic, that information is now three years old and we have to work with what we have, which is the current 2020 law book.
The Rugby Ref has now sought advice from three or four Premiership Referees, who all came to the same conclusion. If a kick is taken incorrectly (from the wrong spot, wrong type of kick etc) then the kick has in fact not legally taken place, and the game has not restarted. So we bring them back to take it again correctly.
However if this is done repeatedly then the referee may consider "repeat offending" or "intentionally infringing", but good game management should prevent things getting that far.
The Rugby Ref