These and many other "dysfunctions" predictably occur over a broad spectrum of species. But since they are atypical and, above all, because we don't like them, they are deemed "errors." Nature didn't know what it was doing, you see, and nature's "intent" was somehow frustrated by nature itself. But nature's incompetence doesn't stop here. It's also horribly inefficient. Take the kidney as an example. If you told me to deliver 100 parcels, each to a unique address, you would probably expect me to handle only one parcel per delivery, right? I mean, if at each address, I unloaded every one of those parcels and then re-loaded all but one, you'd be flabbergasted at my inefficiency, wouldn't you? But this is exactly what happens in a "functional" kidney tubule, and no one in biology has been able to do anything but theorize about why. Nature also seems to have a horrendous track record on standardization of parts. If you thoroughly dissect a randomly chosen cadaver, you'll find anomalies -- of redundancy, of configuration, of displacement and so on. I, myself, have an "extra" right ureter, discovered only when an IVP was performed. I also have a grossly displaced right ileoinguinal nerve, discovered during a hernia repair (and fortunately not cut). Virtually no one's anatomy conforms in all respects to what is found in the pages of Williams and Warwick. Do you want optimal nutrition? Then don't rely on the table of RDAs because almost nobody's optimal nutritional requirements conform to that, either. It's only an average taken from a fairly broad range, and some people are actually harmed by an RDA-compliant intake. How could nature make so many "mistakes"? Could it be that the fault lies in our own arrogant preconceptions? Nah, couldn't be...
Of course not. Everything that can be known can be known through our senses. Including the truth [whatever that is] of that proposition itself :)