Stories like this regularly make the rounds when movies or shows that the original creators put a lot of love and thought into are "remastered" on the cheap. The last one I saw was the story about the garish colors in digital versions of old Pixar movies - amongst others, they intentionally exaggerated green hues in the digital original to compensate for the transfer process to analog film stock which was less sensitive to green. When Disney transferred the movies to digital formats and streaming, they took the digital original 1:1, so the colors now look off (https://animationobsessive.substack.com/p/the-toy-story-you-...)
Discussed here a few weeks ago: https://news.ycombinator.com/item?id=45883788
What happened to the early Pixar movies isn't at all the same, though. They weren't remastered, they were just transferred to a media that they were not originally mastered for.
So odd that they didn't slap a film emulation on top of that. Although maybe not any existing software emulates exactly the film stock they used, any film emulation would look more true than a 1:1.
Part of the reason this one is news is that there's really zero excuse for it being done "on the cheap": HBO can afford the very best, and their reputation kiiiind of depends on it.
Through work I once got into conversation with the guy who did the re-mastering into 96kHz of the ABBA back catalogue. Up until that point CD re-releases of their material was apparently all converted from the cassette masters where they'd massively exaggerated the HF to compensate for the fact that cassette had a notoriously terrible HF response...