Why was "Allah" added in some early Qurans

In this video, Dr. Brubaker shows and briefly discusses examples of “Allah” insertions and other corrections involving the Arabic word for “God” in several early Quran manuscripts. During the first part of the video, Dr. Brubaker highlights and responds to comments from his last video, “Unboxing!”https://www.youtube.com/watch?v=rEfVf…1:08A greeting from Jamal Khan in Pakistan1:24A question Mariem Buenaventura about books, teaching, and reading2:35A greeting from Anthony Patty in Indonesia2:50A question about Hythem Sidky’s critique of Brubaker’s book “Corrections in Early Quran Manuscripts”3:50Comments and advice from RomanoProductions about Dr. Brubaker’s “Unboxing” video and general style of thumbnail images5:39A comment from viewer “om sa” that the manuscripts are not of ultimate importance because the Qurʾan was transmitted by recitation and memorization In the second part of the video, Dr. Brubaker discusses four manuscript corrections:10:54Further information about these corrections and others like them can be found in “Corrections in Early Quran Manuscripts”https://www.amazon.com/Corrections-Ea…and also in the forthcoming volume in the Inârah series, “Die Entstehung einer Weltreligion VI”11:24Brubaker discusses why he considers some “Allah” corrections worthy of attention despite “Allah” being a frequently occurring word in the Qurʾan12:21EXAMPLE 1, Marcel 5, 11r, Q34:27, هو “huwa” appears to have been first written, then erased and replaced by هو الله “huwa allāh” by a later scribe. Thus, this verse was first written “for He is the Mighty, the Wise,” and now (as in the standard text, “for He is Allah, the Mighty, the Wise.”13:16EXAMPLE 2, BnF arabe 326a, 7v, Q7:44, “allāh” inserted as superscript by a later scribe between لعنة “la’nat” and على “ʿalā.” As first written, this manuscript read “a curse is upon (or ‘may a curse be upon’) the evildoers.” The insertion brought this manuscript in line with the standard text, which reads “the curse of Allah is upon (or ‘may Allah’s curse be upon) the evildoers.”14:12EXAMPLE 3, Marcel 11, 10v, Q 33:73, “allāh” inserted over erasure of tail of ب of يتوب in the place where it stands in the standard text. As first written, Allah was still the implied subject: “that He might pardon the believing men and the believing women.” The insertion makes the subject explicit, “that Allah might pardon the believing men and the believing women.”15:03EXAMPLE 4, BnF arabe 340, 23v, also Q 33:73 and covering an overlapping portion with the example just mentioned. المشركين والمشركت ويتوب الله على al-mushrikīn wa-l-mushrikāt wa-yatūba llāh ʿalā “the idolatrous men and the idolatrous women, that Allāh might pardon” has been written over an erasure.