Didn't you see the dented header video that engine masters put out? I think the flow is a concept that's hard to grasp because you automatically want to think of it being in a single direction but the dynamics of a gas and heat expansion changes the behavior so direction doesn't matter as much, also considered this bend is quite far down stream I wouldn't worry about it either.. mufflers made from square boxes claim to flow better even with flat plate perpendicular to the direction of said flow..
paralysis by analysis...