Shaykh Mufeed in his famous book, Kitab al-Irshad. In Kitab al-Irshad, he writes about how the Imam Mehdi (i.e. Qa’im) will–on his return–teach people the “real” Quran. Shaykh al-Mufid writes:

(Imam al-Baqir) said: When the Qai’m from the family of Muhammad, may Allah bless him and his family, arises, he will set up encampments and he will teach the people the Quran as it was revealed by Allah, the Mighty and the High. The greatest difficulty will be for those who have learnt it as it is today, because it differs from its original composition.

Source
Book Title: Kitab al-Irshad (The Book of Guidance)
Author: ash-Shaykh al-Mufid
Publisher: Balagha Books in conjunction with The Muhammadi Trust [1981]
Translated by: I.K.A. Howard
Page: 553

That’s strike two for Shaykh al-Mufid.