When I am trying to engage Christians in dawa and interfaith dialog the question of Jesus and his status is always there and must be addressed. The early gospels of Mark and Matthew refer to him as 'son of man'. Should muslims have an issue with this?
In the Tanakh (Old Testament), the phrase translated as "son of man" is "ben adam" literally "son of Adam", which is a word for a human being.
lō ’îš ’êl wî-ḵaz-zêḇ, ū-ḇen- ’ā-ḏām wə-yiṯ-ne-ḥām; ha-hū ’ā-mar wə-lō ya-‘ă-śeh, wə-ḏib-ber wə-lō yə-qî-men-nāh
God is not man, that he should lie, or a son of man, that he should change his mind. Has he said, and will he not do it? Or has he spoken, and will he not fulfill it?
wayyoˈmer ˈelay benˈadam ˈamod ˈalraglekha vaˈadabber ˈotakh
And He said unto me: 'Son of man, stand upon thy feet, and I will speak with thee.
The Quran uses a similar word to refer to humans, for example:
وَلَقَدْ كَرَّمْنَا بَنِي آدَمَ وَحَمَلْنَاهُمْ فِي الْبَرِّ وَالْبَحْرِ وَرَزَقْنَاهُم مِّنَ الطَّيِّبَاتِ وَفَضَّلْنَاهُمْ عَلَىٰ كَثِيرٍ مِّمَّنْ خَلَقْنَا تَفْضِيلًا
Walaqad karramna banee adama wahamalnahum fee albarri waalbahri warazaqnahum mina alttayyibati wafaddalnahum AAala katheerin mimman khalaqna tafdeelan
And We have certainly honored the children of Adam and carried them on the land and sea and provided for them of the good things and preferred them over much of what We have created, with [definite] preference.
And the Prophet used it as well:
قَالَ اللَّهُ أَنْفِقْ يَا ابْنَ آدَمَ أُنْفِقْ عَلَيْكَ
Allah's Messenger (ﷺ) said, "Allah said, 'O son of Adam! Spend, and I shall spend on you."
يَهْرَمُ ابْنُ آدَمَ وَتَشِبُّ مِنْهُ اثْنَتَانِ الْحِرْصُ عَلَى الْمَالِ وَالْحِرْصُ عَلَى الْعُمُرِ
The son of Adam grows old, but two (desires) in him remain young: desire for wealth and desire for life.
Jesus was a human according to Islam, and being the son of Mary he was a descendant of Adam. So I don't see a problem with using this title, he was of the بَنِي آدَمَ.
Messengers are humans of the Bani Adam:
يَا بَنِي آدَمَ إِمَّا يَأْتِيَنَّكُمْ رُسُلٌ مِّنكُمْ يَقُصُّونَ عَلَيْكُمْ آيَاتِي ۙ فَمَنِ اتَّقَىٰ وَأَصْلَحَ فَلَا خَوْفٌ عَلَيْهِمْ وَلَا هُمْ يَحْزَنُونَ
Ya banee adama imma yatiyannakum rusulun minkum yaqussoona AAalaykum ayatee famani ittaqa waaslaha fala khawfun AAalayhim wala hum yahzanoona
O children of Adam, if there come to you messengers from among you relating to you My verses, then whoever fears Allah and reforms - there will be no fear concerning them, nor will they grieve.
And Jesus was no exception:
مَّا الْمَسِيحُ ابْنُ مَرْيَمَ إِلَّا رَسُولٌ قَدْ خَلَتْ مِن قَبْلِهِ الرُّسُلُ وَأُمُّهُ صِدِّيقَةٌ ۖ كَانَا يَأْكُلَانِ الطَّعَامَ ۗ انظُرْ كَيْفَ نُبَيِّنُ لَهُمُ الْآيَاتِ ثُمَّ انظُرْ أَنَّىٰ يُؤْفَكُونَ
Ma almaseehu ibnu maryama illa rasoolun qad khalat min qablihi alrrusulu waommuhu siddeeqatun kana yakulani alttaAAama onthur kayfa nubayyinu lahumu alayati thumma onthur anna yufakoona
The Messiah, son of Mary, was not but a messenger; [other] messengers have passed on before him. And his mother was a supporter of truth. They both used to eat food. Look how We make clear to them the signs; then look how they are deluded.