@richard...I'll take a guess.

They have heat exchangers in both pods, so could be they're sending the HX exhaust out the same body ports as engine exhaust. The high exhaust velocity might draw more flow through the HX's, something like a jet pump.

If they need more cooling capacity on one side than the other (additional HX, different sized HX on the left for packaging), the mass flow differs per side. If it does, they would likely size each port cross-section to bring the flows to the same exit velocity. The flow velocity would probably be more important than the mass flow since additional external flow around the body can make up for varying mass flow.

Just thinking out loud.