Like with caffeine specifically they have a long history of forbidding its use and then suddenly they reinterpreted it the way you’re suggesting.
I had to think about this. I can’t seem to find any articles in a quick search where church leaders (a Prophet or Apostle) explicitly forbade its use. I have, however, found many excerpts where leaders who do not sit at the head (Quorum of the Seventy, BIshop, etc) have made statements warning against it or even flat out saying that members should not ingest it.
Given the structure and lack of corrective statements coming from above, I would attribute the confusion to local and regional leaders being overzealous by including caffeine explicitly in their teachings. Some have worded things in a manner I would find accurate, such as “high-dose caffeinated energy drinks” or “excessive soda consumption which results in high caffeine and sugar intake.” Others though explicitly call out caffeine as an “evil,” describing experiences with caffeine withdrawals or members deciding to not ingest alcohol, nicotine, nor caffeine. These mentions seem to have drummed up confusion primarily in the 80s (a lot of “Letter to the Editor” publications from this period seem to have been back-and-forth arguments among members, lol).
Initially I didn’t think the history is as “long” as you claimed, but then I realized that the 80s was just forty years ago, and with some results of the topic dating as far back as the 70s, it would mean it’s been an intra-member debate for almost half a century. And half a century is practically a lifetime 😖