negative1 said:

why is using a new mix a bug?

The GOUT was pitched as the "original trilogy as it existed originally in the theatres", which is why they went through the trouble of putting in (or re-creating) the original crawl and flyover for Star Wars. Given that description of what it was supposed to be, the only appropriate mixes for Star Wars would have been one of the '77 mixes.

It's not a technical glitch, but it is a point at which it clearly deviates from the purported design specs--and it's not even a matter of attempting to meet the design specs and doing badly at it (anamorphic could qualify as that), it's just not even in the same ballpark as the goal. I think that qualifies as a bug.

You know, like if your software was supposed to be a Word Processor but it turned out to be a toaster oven. Perhaps fully functional and even good at what it does but still wrong.