Islam Permits Lying to Deceive Unbelievers and Bring World Domination!
You're right! They always call Issa "the son of Mary." My error for mixing them up with the historian-types wo reinterpret the phrase.
Though I did find one Muslim convert who reinterprets the phrase, the general Muslim opinion is as you say.
“But that’s the thing. Muslims don’t believe He is Son of God at all, since Issa al Masih was only one of the 25 prophets. A very important one, but nothing but a prophet. Mormons believe He is a Son of God. Hence my post.”
Many years ago when some Arab friends were working hard to convert me to Islam, they were emphatic that Jesus was not a son of God, but that Mary was a virgin. When I asked who was the father they just looked puzzled and moved the conversation along to another topic.
Good times. We used to drink a lot of beer together during those sessions. I did not appreciate the irony at the time.