Obstruction on Catcher

[Spence]

I heard an umpire tell a coach that there is a new interp on obstruction re: plays at the plate.

Runner coming from 3rd to home - catcher is waiting on the throw and has the plate covered - runner slides before F2 receives the throw. F2 has the plate blocked and upon catching the ball tags the runner for an apparent out.

Umpire yells "that's obstruction."

Coach questions the call and the umpire said something like "its a new interp and that's how I understand it." He said that the catcher cannot block the plate without having the ball.

So,

is this a new FED interp this year?

If the catcher left part (even a very small part) of the plate uncovered I would assume its a legal play. True?