verbum non grata

Reading this article about words used by the Nazis, I stumbled upon verbum non grata. This didn't occur to the writer of the report, but this really leaps to a speaker of a Romance language like myself. The journalist made a pun with persona non grata, which is fine, since both persona and grata agree, both being feminines. Now with verbum non grata you don't have the same accord. Verbum is a neuter word, and all modifying adjectives should agree with it, which would lead us to verbum non gratum. I don't know if the reporter wasn't aware of it since he probably never took Latin (very few do nowadays) or he thought people wouldn't associate gratum with persona non grata, but this is something that immediately draws Romance speakers' attention.