Twitter Bug: do not scale width of player card


We have a player card which was rejected because of the following reason:
“The video frame on your card is too large. Please halve its size.”

We are specifying player dimensions of 250x443 and the actual video being played is 360x640. However, it appears that Twitter automatically scales the video to fit the web page width (our video is in portrait orientation), resulting in our video being displayed at 434x772. (Note that this is larger than our actual source.) Can somebody please advise???