The intent of the 12th man/holder for kickoffs was to ensure that the ball could be kicked in windy weather -- without breaking up the new dynamic kickoff alignment. The rule refers to a tee but does not explicitly require one, hence this loophole...
Richard Hightower said that special teams coaches who were on the committee to create the new kickoff rules will meet Friday to discuss the rules going forward after the Eagles (in Week 2) and Falcons (in Week 1) used punter Braden Mann to hold the ball during kickoffs. Under the new kickoff rules, the ball is supposed to be placed on a tee.
Using a holder was not the intent of the rule, Hightower said, which is why the meeting was called in the first place. He stressed that it will get "corrected."