Possessed FOV in PIE mode

Have been using UE for a few years now yet there is still something that puzzles me in Camera behaviour.
What determines the possessable FOV when you enter PIE mode? It always seems to default to 90.
ie if you have a Piloted Camera, then enter PIE mode, the view becomes ‘Possessed’ and the FOV changes until you hit ‘Eject’. That is unless your camera also happens to have a FOV of 901

How can you change this behavior so that the ‘Possessed’ view does not change the Piloted Camera’s FOV?