A Qur’anic Contradiction in a single verse

The Qur’an claims that if it were not from God, there would be many contradictions in it. However, there is one Qur’anic verse which presents an inherent contradiction! In chapter 12, verse 1, the Qur’an says the following:

If the Qur’an is a “clear Book”, what does “Alif-Lam-Ra” mean? The “clear Book” doesn’t tell you, doesn’t even give you a hint! Not only that, if you explore the issue, you find there isn’t even anything close to a consensus among Islamic exegetes.