HV cooling exhaust tube, missing hatch?

On the very last piece of the exhaust for the HV fan, the piece that goes by the 12V battery and points to the little plastic flappy doors on the side of the car, there is a big hole in the bottom, with an area about the size of a playing card. It isn't visible from the top, but I can get most of a hand into it. Is there supposed to be a door or hatch cover there? It is a very oddly shaped hole as it is on part of the curve of the plastic. But it doesn't feel like it is damage to the plastic, it feels like it was molded to have that hole.

Seems rather counter productive to aim the exhaust at the outlet doors but have a gaping hole in the pipe about 6" upstream. That is going to dump most of the hot air into the trunk area. On my car that is usually covered by the security screen, so I guess it will go out eventually, but not before heating up the whole trunk.

 

Looked this up in the service manual. Apparently that hatch is there to cool the 12V battery. Or maybe warm it. In any case, blow on it.