The player character is one of 8 chosen from a menu. Anyone of them can be used. The default UE player mesh is the base character and BP for the other 8. If I make a change to that character it affects all of the others. In the project settings “Default Pawn Class” is set to the correct base pawn that controls the other 8. I hope that is what you meant.
As a side note, the level runs perfectly in PIE and nothing else. I figured that was a clue but could find no info to follow it up.