Does unintentionally changing a letter or word when reciting the Qur’an, due to an unpurposed error in sight or memory, and continuing with the incorrect recitation for some time before correcting it, constitute an alteration of the Qur’an that necessitates apostasy (ridda) or requires uttering the Two Testimonies (Shahadatayn)?

It is not permissible for you to continue reading while aware of the mistake, and the claim of beautifying the voice is not an excuse for it. Rather, some scholars have even gone so far as to say it is not permissible even with doubt, as mentioned by Ibn Hajar al-Makki. This act does not necessitate apostasy unless it is accompanied by the intention of disgracing the Quran or truly altering it.