I drive in M mode probably 90% of the time, so all 4 exhaust pipes theoretically should be working. However, looks like the flap on the right side is not (see pictures taken with M mode on). I tried to nudge the flap with a screw driver just to make sure its not stuck in a closed position and verified that it opens easily and there is a spring holding it shut.

Is this broken or by design?

Attached Images