Is a man's marriage to his milk-sister, with his knowledge of that and his insistence on the marriage, claiming that she was nursed only once or twice, considered zina (fornication/adultery), especially since the hadith states: "five satisfying sucklings"?

Scholars have differed concerning the amount of suckling that establishes prohibition. The preponderant opinion is that it is five known sucklings, based on the Hadith (definition) of Aisha (may Allah be pleased with her) that ten sucklings used to establish prohibition, then they were abrogated by five known sucklings, and the Prophet (peace be upon him) passed away while this was among what was recited [from the Qur'an]. Based on this, the marriage is valid and not considered zina if the woman was only suckled once or twice. The correct wording in the Hadith is "known" (معلومات) not "satiating" (مشبعات).