Is exaggeration in correcting recitation, to the extent that it includes both the obligatory and the recommended, considered a sin?

A reciter of the Qur’an must recite the letters and vowel markings correctly and clearly. As for anything beyond that, such as mastering the elongations (mudud), nasalizations (ghunnah), assimilation (idgham), articulation points (makharij), and characteristics (sifat), it is desirable (mustahabb) but not obligatory (wajib).

There should be a differentiation among students in teaching the Qur’an according to their level. For the beginner, it is sufficient to correct his letters and vowel markings, then gradually move him to the simpler rules of Tajweed until he masters the recitation. A skilled teacher corrects each student according to his level. For some, he may only correct the vowel markings, while for others, he may correct the articulation points and characteristics. Exaggeration (takalluf) in everything is blameworthy.