Seemingly this word crept into this hadith through the means...

Seemingly this word crept into this hadith through the means of idraj (inclusion), that was common among men of hadith, so as it be taken by the narrators as a reliable basis in whatever they report from others through mistake, or misconception, or error, or misunderstanding. Through this they intended to ward off the sin of lying and evade any interdiction in narrating, as that who errs being not sinful.

Or that this word (deliberately) was inserted in the hadith in order that those who were unpurposely composing and fabricating traditions, could justify their practice, to support by it their utterances and gain the trust of people.

8 The Compositions: Throughout its whole history, Islam was never inflicted with a misfortune more dangerous than those composed traditions, the fabrication of which was done by both the enemies and lovers of Islam, for numerous reasons we demonstrated in their places. Beside the Israeliyyat which were disseminated by the Jews, like Ka’b al-Ahbar and Wahb ibn Munabbih and others.

Moreover we can refer to the Masihiyyat and other similar fabrications that were foisted into our religion from the un-Islamic religions and creeds, but believed and accepted by Muslims without any investigation, or taking notice of them (their being fabricated).

Abu Hurayrah: Abu Hurayrah was the most prolific Companion in reporting (traditions) from the Messenger of Allah, though not keeping the Prophet’s company more than a year and nine months, as I verified and recorded in my book Shaykh al-Mudirah, 9 with his narrations containing that abundance of troubles which survived for a long epoch and will be there for ever.

Because of these facts I have dedicated for him a separate special exposition in which I fulfilled my duty toward knowledge, seeking only the truth, citing in it whatever be in his benefit and whatever be against him, fearing no one in demonstrating the truth, or hesitating in disclosing knowledge, as truth is verily superior and greater than Abu Hurayrah.

Collecting and Inscribing the Qur’an: Before giving detailed information about inscription of hadith, I would like to pave the way with a short recapitulation on writing down the Qur’an, in which I stated a complete abridgement of this subject, so as to make clear for people how our ancestors were seeking full accuracy and extreme confirmation when collecting the Qur’an.