Interesting to know that 'not described well enough to implement' is valid grounds for challenge. Thaks for clarifying that. However, in the example you cite it says that "the Board reaches the conclusion that the invention claimed in claim 1 of the main request is disclosed in a manner sufficiently clear...", so the challenge did not succeed on those grounds. The challenge in fact succeeded on 'lack of inventive step' (unless I am misreading that post).