That happens more than it should. The Six Foot rule during the pandemic was based on a slide from a conference presentation in the 50s, citing a 1930s tuberculous study and wasn't relevant to viruses. A Medical researcher got onto this early as "social distancing" wasn't working and she had trouble finding any credible source and found the 1930s paper and then started following citations back into the 1950s to one slide. It was just repeated on and on with no continuation of the actual source citation.

[edit] here is a link to the original NYT article from June of 2020 https://archive.is/ZuSyc

https://www.wired.com/story/the-teeny-tiny-scientific-screwu...

Archive link for research and education. https://archive.is/z14Ia