Somebody's too close to the Falco when he does it.
If you're not close and you try to do it you'll just end up getting double lazered into dacused to the face.
A good falco or at least the falco I fought at COT5 dosn't do phantom until I'm close enough that I can't react to it. And when I'm not close enough to attack he'll just spam lazers and dacus.
If you want to know how the match went it went like this, Falco runs away from you on BF shooting lazers, get too close and he'll phantom to the other side, but he'll only phantom if you can't punish it if you shield it, try to jump and nair, get shot in the face into phantom or DACUSed. Try to go over the platforms, yeah by the time you get to the other side, he'll be on the side you just came from. Get a small hit every once in a while, but doesn't compare to the damage he is dealing to you. Then he lets you in one time on purpouse so you can eat a fsmash to the face and die at 60%.
Crouching/ledgrabbing/scouring all **** Falco but its no good when he gets the first hit, which he will always get.
My solution to this dumb matchup is to pick a different character. Unfournatly, Diddy has a huge problem with him as well.