On sunnah.com the Hadith is graded as Hasan in chain. Does that mean the Hadith is not truly Hasan? Meaning, it is only Hasan in chain but the Matn (content) is defective?
The next hadeeth is about the same thing. Sheikh Albaani has declared this one Saheeh:
On the day of the conquest of Mecca, Abdullah ibn Sa'd ibn AbuSarh hid himself with Uthman ibn Affan.
He brought him and made him stand before the Prophet (ﷺ), and said: Accept the allegiance of Abdullah, Messenger of Allah! He raised his head and looked at him three times, refusing him each time, but accepted his allegiance after the third time.
Then turning to his companions, he said: Was not there a wise man among you who would stand up to him when he saw that I had withheld my hand from accepting his allegiance, and kill him?
They said: We did not know what you had in your heart, Messenger of Allah! Why did you not give us a signal with your eye?
He said: It is not advisable for a Prophet to play deceptive tricks with the eyes.
The hadith according to respected hadith scholar Shuayb Al-Arna'ut is Saheeh Ligharihi. This means that this hadith by itself, from its isnad only, is not sahih but that this same hadith is repeated somewhere else with a sahih isnad. For this hadith, is is repeated in Al-Mustadrak 3/45 with a sahih isnad according to Al-Hakim.
Al-Albani also concurs with this as he put this hadith in his "Sahih Abi Dawud" book of hadiths and marked the isnad as hasan.
Isnad means chain of narration in case you did not know.
Furthermore, I'd like to mention that matn criticism is separate from isnad criticism. There have been hadiths where their isnads were considered authentic but hadith scholars completely ignored them due to their matn. Imam al-Bukhari himself rejected perfectly authentic hadiths when he considered their contents to be ridiculous, as in a hadith that claimed something would happen within 200 years that never happened.
For more info on this topic, you can check out this paper by Muslim scholar Dr. Jonathan AC Brown: