"The cult of St. Gregory of Narek will be marked on 27 February in the Roman Martyrology. He will be defined as monk, doctor of the Armenians, distinguished for his writings and mystic science."
http://vaticaninsider.lastampa.it/en/the-vatican/detail/articolo/gregorio-gregory-narek-39333/
Is this a recent addition/change to Feb 27? I was under the impression that there was an October 13th date.