Assalaamu alaykum. We pray behind a Hanafi Imam who, if there is a need to perform sujud as-sawh (prostration of forgetfulness), does it in this manner: After reciting the tashahud [not the darud and du'a ma'surah], he gives salam to the right only and then performs sujud as-sawh and again recites the full tashahhud including darud and du'a ma'sura and then finally gives salam to both sides and finish the prayer. However, we know something different from the hadiths. Q.1: What is the evidence for that with reference to the Sunnah and Hanafi Fiqh? Q.2: Should the muqtadi do the same if doing so (for the imam) is not correct in this way?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger.

This imaam's action conforms to the views of the Hanafi School of Fiqh; the following lines shall shed light on this topic in details.

Al-Kaasaani wrote, "According to our school of Fiqh, it is recommended to perform the sujood as-sahw after the tasleem (i.e. concluding the prayer), whether the worshipper has added or omitted an act of the prayer entailing the performance of sujood as-sahw." Then he highlighted the different scholarly views in this regard and the supportive evidence held by the Hanafis, adding, "When the praying person finishes the last tashahhud, he recites tasleem, then recites takbeer, performs the two sujood as-sahw, and then raises his head reciting takbeer then recites tashahhud, invokes blessings and peace upon the Prophet and recites the reported supplications. This is the opinion adopted by Al-Karkhi and the majority of the Hanafis from the area beyond the river..."

He also added, "This is the recommended manner for performing it (sujood as-sahw); however, it is permissible to perform it before or after the tasleem. If the worshipper performs it before tasleem, he is not required to repeat the prayer because he has already performed the pillars of the prayer. However, by doing so he has neglected the recommended manner of performing it, which is after tasleem..." [Badaa’iʻ As-Sanaa’iʻ]

Az-Zaylaʻi wrote:

"The third view pertaining to what should be done after performing sujood as-sahw is, as underlined in the book, reciting the tashahhud and tasleem after performing sujood as-sahw. This is evidenced by what has been narrated by Abu Daawood that the Prophet made two prostrations for forgetfulness and then recited the tashahhud and then did tasleem. Scholars held different opinions, though, regarding the manner of performing tasleem; some maintained that the praying person should make two tasleems (one to the right and one to the left); this is the most likely correct view, holding the (unspecified) reference to the tasleem in the above cited hadeeth to indicate the normal manner of performing tasleem. This view was adopted by Shams Al-Ai'mmah. Fakhr Al-Islam asserted that one tasleem in the direction of the Qiblah is adequate because this tasleem is intended to be a salutation rather than an act of concluding the prayer. Some scholars held that the praying person should perform one tasleem to the right side. Khawaahir Zaadah said: 'The praying person should not perform sujood as-sahw after two tasleems because it will be considered as external talk (uttered outsied the prayer).' The praying person should invoke blessings and peace upon the Prophet and recite the reported supplication after performing the two prostrations of forgetfulness, and this is the most correct view in this regard because they are performed at the end of the prayer. This opinion was adopted by Al-Karkhi. It is also said that the praying person should invoke blessings and peace upon the Prophet and recite the reported supplication in the first sitting for Tashahhud (before Tasleem), but At-Tahtaawi stressed that each sitting position in the prayer ending with a tasleem should include invoking blessings and peace upon the Prophet . Based on this scholarly view, the worshipper should invoke blessings and peace upon the Prophet in both sittings. Other scholars, on the other hand, held that the early Hanafis such as Abu Haneefah and Abu Yoosuf differed with the later ones on that issue. Abu Haneefah and Abu Yoosuf maintained that the praying person should invoke blessings and peace upon the Prophet in the first sitting for tashahhud (before Tasleem), whereas Muhammad (ibn Al-Hasan) held that the praying person should invoke blessings and peace upon the Prophet in the second sitting after performing the two sujood as-sahw; that is because Abu Haneefah and Abu Yoosuf maintained that the tasleem marks the end of the prayer according to their scholarly view; therefore, they considered the first sitting before sujood as-sahw as the one concluding the prayer, in which the praying person should invoke the blessings and peace upon the Prophet and recite the reported supplication so that he would conclude his prayer after completing the due pillars, acts of Sunnah, and recommended acts in the reported manner. It says in Al-Mufeed that this is the most correct view in this regard. Muhammad (ibn Al-Hasan), on the other hand, held another opinion that this sitting is not the one concluding and ending the prayer and that the praying person should invoke the blessings and peace upon the Prophet and recite the reported supplication in the second sitting after sujood as-sahw, for such a sitting is the one that concludes the prayer in this case." " [End of quote]

As for following the imaam when he commits an error in the prayer, when the imaam commits a mistake that entails invalidating his prayer such as missing one of the pillars of the prayer or doing whatever invalidates it, then it is incumbent on the person who prays behind him to stop following him, and it is impermissible to follow him. It is also allowable for the praying person to leave the congregational prayer before it ends (and complete it individually) for whatever of the legitimate excuses and sharee'ah-acceptable reasons.

Ibn Qudaamah said:

"It is allowable for the one who started his praying while intending to pray behind the imaam in the congregational prayer to leave the congregational prayer and complete the prayer individually for a valid excuse. It has been narrated on the authority of Jaabir that 'Muʻaath ibn Jabal used to pray along with the Prophet and then would return and lead his people in prayer. One night, the Prophet delayed the prayer. Then, Muʻaath prayed along with the Prophet and then returned to his people and led them in prayer and recited Soorah Al-Baqarah. A man turned aside and prayed alone. The people said to him, 'Have you become a hypocrite, O so and so?' He replied, 'I did not become a hypocrite!' He then came to the Prophet and related the incident to him. Thereupon, the Prophet said, 'O Muʻaath, are you a trouble maker? (He repeated it twice) Recite such and such; recite such and such (of short soorahs),' he added. The narrator Abu al-Zubayr mentioned the names of some soorahs such as Al-Burooj (85), Al-Layl (92), At-Taariq (86), and Al-Ghaashiyyah (88), as mentioned by the Prophet ..." [Al-Bukhari and Muslim]

The Prophet did not command the man to repeat that prayer nor did he rebuke his for his act. Examples on the acceptable excuses for deeming it permissible to leave the congregational prayer abruptly before it is finished are the hardship incurred by prolonging the prayer by the imaam, illness, or fear of being overcome by sleep or whatever may invalidate the prayer, fear of losing one’s belongings or companionship, or that he fears that the person praying by his side would leave the line and he would find no other person to stand by his side in the row, and the like..." [Al-Mughni]

Ibn ʻUthaymeen wrote:

"If he joined the congregational prayer in its beginning and then realized that the imaam neglects the pillar of (attaining) calmness and tranquility during the prayer and that following the imaam would inevitably result in neglecting that pillar, then in this case it is incumbent on him to leave the congregational prayer and complete the prayer individually because following the imaam in this case would necessarily result in neglecting one of the pillars of the prayer, and would subsequently result in invalidating his prayer..." [Majmooʻ Al-Fataawa]

Allaah knows best.