1/ Lactate does not cause lactic acidosis, and we've known this for more than 20 years: https://doi.org/10.1152/ajpregu.00114.2004

I believe this review paper found by reading xkcd comics, but I can't find the relevant strip right now. I guess the reason few people know this (besides not reading xkcd) is that this newish knowledge had little use. According to the video, lactate supplementation was not feasible until recently, because the available products were unpalatable.

+