Why did the linguists object to Abu Ja'far al-Madani's recitation of "وإذ قلنا للملائكة" (And when We said to the angels) with a dammah on the ta' (تُ), despite the frequent transmission of the narration, claiming that there is no small idgham of two similar letters in his recitation due to the madd silat mim al-jam'?

No attention should be paid to anyone who denies the recitation of Abu Ja'far, for he is an Imam from the Tabi'in (successors) and his recitation is among the continuously transmitted (mutawatir) recitations. Al-Jazari and Abu Hayyan spoke about the ضم (damm/ضمّ — fronting of the lips, like the 'oo' in 'moon') of the taa’ (ت) in "al-Mala’ikah" (الملائكة) in five places, and they clarified its linguistic justification. This included the 'ishmam' (إشمام — slight rounding of the lips for a vowel sound without fully pronouncing it) of its kasra (كسرة — the vowel sound 'i') into a damm, or its damm due to the difficulty of transitioning from the kasra to the damm, or its resemblance to the hamzat al-wasl (همزة الوصل — connecting hamza). Abu Hayyan mentioned the statements of Al-Zajaj, Al-Farisi, Ibn Jinni, and Al-Zamakhshari, who found fault with this recitation, but then he refuted them by stating that it is a dialect of Azd Shanu'ah and that Abu Ja'far is a great Imam. As for the idgham (إدغام — assimilation) of two identical letters, it is frequent in his recitation, but he does not perform idgham on the mim of pluralization if there is an intervening letter, such as the vowelized waw in "wa lakum ma kasabtum" (ولكم ما كسبتم).