I myself have a p3a. I bought my brother a P4 standard for Christmas.  Everything worked besutifuly out of the box. Not one problem with eithet drone. My question is has anyone with a p4 ever noticed there's a button on the top in the top middle of the controller, between the handle.  On my p3a its same style emblem only it isn't a button.  Curious minds want to know.

Would you please take a picture and upload it here? thanks.

On my P4 controller the is just the dji logo  in the middle  of the top edge

My P4 remote has the same thing. It right in between the antennas. Also tho I don't think it does anything you wouldn't know that it's a button. When pushed you can definitely hear it click

I correct myself it is between the antennas and not between the handle. It is the same logo that is on my P3A only it is a button that doesn't appear to do anything..