Yeah this has been bad for quite some time now. See:
It’s been that bad that Touring Plans has stopped publishing wait time data through their daily blog posts. It was just too confusing with all the different terms like estimated, observed, actual, posted which didn’t line up correctly with the historical TP data. And since the posted times are easy to get accurate data for, TP would just use those numbers and call them the “average wait time”, which is not really right and produced complaints. 