Odd case of unicode character not accepted in one attribute but valid for another

I was watching the Czech film, Démanty noci, and the credits are in Czech. I know that recently we have been able to add "as" attributes with the correct spelling in Czech, so I tried it here. Oddly, the same spelling of the attribute (Arnošt Lustig) in the attribute field of writers is accepted once and rejected in another.

(as Arnošt Lustig) is accepted as a valid attribute.

(based on Arnošt Lustig's novel "Darkness has No Shadows") complains that the unicode is not support.

As these are both attributes in the same field in the same area of the database, I'm at a loss as to why this would happen. See below: