Well, it was changed after, anyway:
Fedeli, A. (2005). Early Evidences of Variant Readings in Qur’ānic Manuscripts. Die dunklen Anfänge: Neue Forschungen zur Entstehung und frühen Geschichte des Islam, 293-316.
See also
Al-Imam, A. A. (2007). Variant readings of the Qur’an: a critical study of their historical and linguistic origins. International Institute of Islamic Thought
Small, K. E. (2011). Textual Criticism and Qur'an Manuscripts. Lexington Books.
The problem is this tradition runs into problems rather quickly. I've attached a review paper on this matter from A Cambridge Companion to the Qur'an
Sorry to correct you.. None of the references which you have given shows that Qur'an was changed. The first paper discusses about the variants in the writing styles of the Quranic manuscripts. The second document discusses about the different dialects(qira'as) of the Quran. Here, the words are exactly same, but with different recitation styles. I didn't get the third document online. I saw a Wikipedia article about it. It also doesn't show that Quran was changed.The author tries to criticize the Qur'anic manuscripts and concludes that a critical text of the Quran cannot currently be constructed.
The paper you have attached also doesn't show that Qur'an was changed. What I could understand from this paper is that either the author had a very week understanding of the Qur'an or he is intentionally trying to misguide the readers who are ignorant of the Qur'an. Someone who knows Qur'an would even doubt, whether the author had even seen the Qur'an.
In the first part of the paper, the author tries to show that many of the verses in Qur'an indicates that God isn't the speaker.
This is one of the examples which he has given:
"Indeed, Allah is my Lord and your Lord, so worship Him. This is a straight path."" Quran (43:64)
The author is trying to say that, since its written 'my Lord' and 'your Lord', I.e God is referenced to in third person form, it shows that the speaker is not God.Anyone who bothers to make a slightest attempt to open the Qur'an and read the previous verse would understand that its the dialogue of Jesus to his people. The verses are like this:-
And when Jesus brought clear proofs, he said, "I have come to you with wisdom and to make clear to you some of that over which you differ, so fear Allah and obey me,
Indeed, Allah is my Lord and your Lord, so worship Him. This is a straight path."
Qur'an (43: 63-64)
In the next half of the paper, the author complicatedly explains the recompilation of Quran at the time of Usman bin Affan, by which Quran was unified into a single dialect.