Your anecdote seems to clash heavily with the results of the benchmark announced in the article. I suppose that is part of the jagged experience of agentic AI
Top tier tax professionals can do pretty well on this benchmark (better than agents) but won't hit 100%.
The kind of people spending time preparing oodles of returns would not do very well on this metric, though (especially midway through that pile of returns, as opposed to "think carefully about this trick question").