This is interesting as it runs counter to what many people think about current AI. Its performance seems directly linked to the quality of the training data it has. Here the opposite is happening; it has poor training data and still outperforms humans. It's not surprising the humans would do badly in this situation too; it's hard to keep up to date on things that you may only encounter once or twice in your entire career. It's interesting to extrapolate from this observation as it applies to many other fields.
One of the authors of the paper goes into more detail on Twitter.