I don't think HFO was a mistake, just the documentary. However, it is important to note that HFO was the only time order was changed until the doc credit fiasco. That's why I speculated it might have been a live arrangement thing.
While I'm not happy about how the doc thing happened, in the end, it's on the interns. If they're like my students, they think research means Google. Only if they can't find something on the Internet do they rouse themselves to actually seek out hard copies! This is especially true if they're in a hurry. Unfortunately, as I tell my students, that can lead to problems.
I hope the Eagles fix it like they did LROOE's credits. Remember that the first print of that also contained songwriter credit errors.