I had a similar problem where the level was creating a new pawn oriented to the editor camera instead of auto possessing the pawn I had in the scene, even though I had this code in my pawn constructor:
AutoPossessPlayer = EAutoReceiveInput::Player0;
I found there is a checkbox in the Details of the Pawn instance that says “Auto Posses Player” and it was set to “Disabled”. I had to set it manually for the correct autopossessing to work. Still not sure why the code didn’t set it for me.