The authors of the site allege there is a contradiction between Pharaoh’s repentance in the face of death as according to Surah 10:90-92, Pharaoh repented in the sight of death and was saved but Surah 4:18 says that such a thing can’t happen.
When Pharaoh was drowning, he declared: … “I believe that there is no deity except that in whom the Children of Israel believe, and I am of the Muslims.” [10:90]
Allah responded to that declaration of faith as follows:
Now? And you had disobeyed [Him] before and were of the corrupters? So today We will save you in body (i.e., physically preserve) that you may be to those who succeed you a sign. And indeed, many among the people, of Our signs, are heedless [10:91-92]
Despite his declaration of faith at the very last minute, the following verses clearly indicate that Pharaoh will be one of the companions of the hell fire:
And he was arrogant, he and his soldiers, in the land, without right, and they thought that they would not be returned to Us. So We took him and his soldiers and threw them into the sea. So see how was the end of the wrongdoers. And We made them leaders inviting to the Fire, and on the Day of Resurrection they will not be helped. [28:39-41]
And We did certainly send Moses with Our signs and a clear authority to Pharaoh and his establishment, but they followed the command of Pharaoh, and the command of Pharaoh was not [at all] discerning. He will precede his people on the Day of Resurrection and lead them into the Fire; and wretched is the place to which they are led. [11:96-98]
Pharaoh repented only when death approached him. And repentance at the face of death is not accepted [4:17-18]. The Qur’an declared that the matter concerning Pharaoh’s end constitutes an End-time sign:
And when they angered Us, We took retribution from them and drowned them all. And We made them a precedent and an example for the later peoples. [43:55-56]
Pharaoh was discovered in 1898 which confirmed the preservation of his body and a divine prophecy in the Qur’an was fulfilled.