it was changed because it couldn't be made to work, it was bugged out, the attempt was made though. Im not a fan of the set whatsoever personally but they only undid it because they had to.
From CPH on page 5
"Sadly the implementation of Attune has to go back to a toggle. There will be a few more mechanical adjustments on how it all works though, but Attune will have to be a toggle. Double click accidents is something that will have to be addressed via engine tweaks at some later time. "