The wording is definitely not clear enough in that section, however I don't think this is the intended reading (and I'm hoping we get clarification on this) -- the pardon would be an official act, but according to footnote 3 the sale of the pardon and discussions about that would not be included in the bar on evidence of the official act, because they're not considered part of that official act. It seems (with the footnotes considered) to be a very narrow interpretation of "official act," which does seem to contradict the plain reading. Very annoying.