When those results came in, they revised their recommendations, expressly in the context that new information was responsible for the changes. That’s how you create policy in accord with the scientific method- you change recommendations when better information becomes available.
This was mischaracterized by certain outlets and individuals as lying. And that narrative captured the minds of an unfortunately large segment of the populace.
The TV/video media bears some responsability in this, IMHO. Their formatting of information tends to cut an expert saying "According to the few datapoints we have, and extrapolating from earlier epidemic outbreak, we think it is probably the best course of action to do X" to "the best course of action is to do X" and later, "New information have made use revise our opinion, and now, again it's probable that the best course of action is to do Y" to "the best course of action is to do Y". It might be necessary to shorten things, but it misses important points and helps people who accuse them of lying by providing direct contradictory statements, while the true statement were more nuanced.