I have read numerous times where it was posted in the local newspaper that "The Governor gave written permission for (a specific number) of State Guard members to be transferred to the Presidents command.
So, evidently somebody raised a fuss about it and now he's following the rules with his "written permission".
Hell, it might be nothing more than a professional courtesy. I do know no President has ever fully submitted to the "War Powers Act," but that seems to be an intra-branch battle they don't feel a need to fight. Usually they'll perform just enough of it's requirements to make the Congress look like they're trying to usurp Executive authority if they go after him in the Supreme Court, near as I can tell.