Maybe he saw something, but wasn't confident enough to flag until he had more info that the main ref could give him. No problems with that.
Oh aye, the vital all important intel that the ref had. I overlooked that.
More likely the other way around tbh. Ref thought it was, checked something with the lino.
Indeed, but whichever way around, why hastily flag or blow the whistle when they're not sure yet and feel they could make a better decision by concerting.
Edit: Exactly, Dr Venkman.