I've never really looked at my lens apertures that closely but I've never noticed an asymmetry as prominent as that. If you bought it new and it's covered you could try to get it replaced just so you'll feel better about it, or at the very least not have to worry about it haunting you if you sell it someday. Though to be honest, I'm not sure it's significant enough that I'd have noticed it if you hadn't mentioned it.
I doubt it'll affect much anyway, in most scenarios if you're stopping down that much you won't have out of focus points to worry about the shape of anyway.
Anxiety about this kind of thing is the reason I don't obsessively examine my gear anymore. It's easier on the sanity to only pull out the microscope if the final images are suffering somehow.
Bookmarks