From reading the article, it seems the Orthodox parish in Verin Dvin they are talking about is Russian. The second to last paragraph says there is no Armenian church there. However, the article also makes the statement that the Assyrians living in Armenia are either Orthodox or Catholic. In that sentence, they are probably talking about the Armenian Church. It could be the author doesn't know the difference between the Russian and Armenian Churches.
The Armenians and Assyrians, although Christologically very different, are geographically next door neighbors, so to speak, and have both been persecuted by the Turks and other Muslims. That sort of thing brings people together despite theological differences. It is not uncommon for Assyrians and Armenians to intermarry. I've known Assyrians who speak Armenian and Armenians who speak Assyrian. Also, it is not uncommon for Assyrians and Armenians to take communion in each other's churches, even though there would be canons against it.