Ibn al-Shiḥnah al-Ḥanafi [d. 815 AH] – “If the ḥadith is authentic, yet it’s contrary to the view of the Madhḥab [Ḥanafi school], then act upon the authentic ḥadith; this will be your methodology, and the one [acting upon the authentic narration contrary to the view of the Ḥanafi school] is still regarded a Ḥanafi, because it is authentically proven that Imam Abu Ḥanifah said, “If the ḥadith is authentic, then it is my Madhḥab.”
→ Ḥashiyat Ibn ‘Abidīn – 1/71 | Ibn ‘Abidīn [Dar al-Kutub al-‘Ilmiyyah] | Translated by: Abu Dawūd [Mustafa b. Saalih] al-Hushayshi
After relating this principle, and the elucidation by Ibn al-Shiḥnah from “Sharḥ al-Hidayah”, Ibn ‘Abidīn [d. 1836 AD] explains that this principle is for someone who is adept and proficient in the study of ḥadith.
However, since the time of Abu Ḥanifah, a time that preceded a vast majority of the earliest scholars who ventured to compile ḥadith works, there are a great many reliable compilations composed by unanimously accepted scholars who endeavoured to compile, and sift through, works of ḥadith – Narrations that Imam Abu Ḥanifah and his disciples had no access to.
The aforementioned principle, that Imam Abu Ḥanifah established, confirms his lauded wisdom and insight. Far from being a provisional discretion, it proves his advertence in understanding that if an authentic narration reaches the people and presents them with a view contrary to his view then precedence is given to the narration over his opinion.
Imam al-Albani [d. 1999 CE] explains this principle further: “This is from their accomplished understanding and piety, in their indication that they do not inclusively comprehend the ENTIRE Sunnah [every aspect of it]. They may utter something that is ultimately proven contrary to the Sunnah that has not reached them, yet, they order us to adhere to the Sunnah [by giving precedence to the authentic narration], and to incorporate the authenticated understanding into their Madhḥab.”
→ Sifat-Salaat-an-Nabi – Pg. 46 | Imam al-Albani [Edition: al-Ma’arif, Riyadh] | Translated by: Abu Dawūd [Mustafa b. Saalih] al-Hushayshi
Anyone choosing to be at variance with a unanimously accepted narration proven authentic to them just because it is contrary to a view of Imam Abu Hanifah, after it is proven that the narration did not reach the Imam, but they still choose to favour the opinion and give it precedence over the authentic narration is, in effect, going against the Imam and his Madhḥab.
May Allaah have mercy on him.