I've been deep in the docs for the past couple months, and I have never found them to be inaccurate. A bit sparse sometimes, but on the other hand the source code is very well commented. Between the two you can find your way without too much effort.
Digging into a framework's source code is natural to the latter group, but utterly alien to the former.
Documentation written for the latter group describes mechanisms, design principles, APIs, etc. The former group instead requires examples and step by step tutorials.
Both will call documentation terrible if it doesn't conform to their expectations.