Well versed in the theory of classification, he was poorly versed in its practical application, and I doubt that he could tell a sperm whale from a baleen whale!
A lot of people may not be very well versed with the science, the facts of climate change… to be honest, they can at times be quite complex, quite dense.
That minister was galbet, or admiral of the realm, very much in his master's confidence, and a person well versed in affairs, but of a morose and sour complexion.
Even those who are well versed in psychological disorders like depression, anxiety, and schizophrenia may have a shallow understanding of personality disorders, which can contribute to the stigmas that are attached to them.