I can only guess it’s a matter of timing. It’s possible to get a Controller without a ControlledPawn. Controller is an independent actor and it only gets its ControlledPawn after a Posses call. Before that it’s just a pawn-less Controller 
So, this piece of blueprint you’ve attached a screenshot of, when is it called? If it’s on BeginPlay then it may be still too early. OnPosses would be a better place if you want to use data from the ControlledPawn.
Hope it helps,
–mieszko