St. Ladislaus, the king of Hungary, banned marriages with Jews in the 11th century. There also was a time when convents were segregated. There were cases of people not being able to enter religious orders due to racial segregation. Possibly the most famous case is of Ursula de Jesus, a former black slave who was forbidden to enter a religious order in 17th century Peru. Instead she was permitted stay within the convent as a servant.
But he did not pass a law banning the marriage between an Hungarian and a Khazar, and separating Jєωιѕн converts from religious life was a sign he did not trust those converts (and I am sure he had his reasons), but this is still not racial segregation. So his laws were against a religion, not a race.
I bet he did not ban the marriage between a Hungarian and Khazar if they were both Catholic.