1. They stated, more assertively than they probably should, that they believed the virus was contained in Wuhan and not spreading in the community (that's the "no human-to-human transmission" quote that gets taken out of context).
2. Their statements that people should not try to acquire PPE masks were poorly phrased and seemed to imply that masks don't work (obviously they do).
3. There was that one incident, not related to the outbreak really, where a WHO official hung up the phone rather than take questions about Taiwan (for geopolitical reasons, Taiwan is not a member of the WHO). This led to a thousand "WHO is in China's pocket" takes.
I mean, just in general the WHO has not comported themselves well here. There's been plenty of routine incompetence to complain about, and frankly they haven't really don't much to help.
But the political vitriol you hear about them is 100% blame shifting. Most of the people yelling loudest about the WHO failing to give good advice about this dangerous disease tend to argue in other contexts that the disease isn't so dangerous, we shouldn't be forced to wear masks, the economic damage is too great, liberty is at stake, etc...