Any possible way you may of gotte. Some kind of debris oil silicone in the oil passage on the front cam cap? That passsage is whats feeds the tunnel in the cam that feeds the phaser. I've seen it happen before on a stock cam swap, not on a Mustang, but an F150. My buddy changed out his phasers and some followers and cam that got wiped out, called me in anguish over these same DTC's. Scoped it and found the timing was way off on the passenger bank. Pulled the valves covers to see if the timing lined up, it did. Then out of curiosity pulled the front cam cap on the passenger bank and it had a bit of silicone on it. Dunno how, but it did. Check that cap and see if the tunnels in the cam are clear also... Might be worth a shot.