Among the issues in dispute is the question of liability for the pre-emptor’s warranty: does it rest on the buyer or on the seller? Mālik and al-Shāfiʿī hold that it lies with the buyer, while Ibn Abī Laylā holds that it lies with the seller.

Mālik’s reasoning is that the right of pre-emption is only triggered for the partner once the buyer’s ownership has become established and sound; accordingly, the warranty must be borne by him. The opposing camp argues that pre-emption becomes due by the very act of sale itself, so its exercise both annuls the original sale and constitutes a new contract for the pre-emptor.

All are agreed that mutual cancellation (iqālah) does not invalidate the right of pre-emption, whether one regards the iqālah as a new sale or merely as a rescission.

The Mālikī jurists differ over whose liability it is in the case of iqālah. Ibn al-Qāsim says it is upon the buyer; Ashhab says the pre-emptor may choose.

Another point of disagreement concerns the situation in which the buyer erects a building, plants trees, or the like on the purchased share before the pre-emptor asserts his right. Mālik rules that pre-emption may not be exercised unless the buyer pays the pre-emptor the value of what he has built and planted. Al-Shāfiʿī and Abū Ḥanīfah, however, deem the buyer a trespasser; the pre-emptor may either pay him the value of his constructions as if removed, or take the property after demolition.

The root of their dispute is the ambiguous status of the buyer’s conduct—while knowing that pre-emption will apply—between the behaviour of a usurper and that of a lawful purchaser whose title is later displaced. Having built and planted, he occupies a middle ground between the two. Those who emphasise the aspect of subsequent entitlement deny him any right to compensation; those who emphasise the aspect of transgression allow the pre-emptor either to remove the improvements or to pay their value once removed.

Another disagreement arises when the buyer and the pre-emptor dispute the purchase price. The buyer says, “I bought the share for such-and-such,” while the pre-emptor says, “No—you bought it for less,” and neither party has evidence. The majority of jurists accept the buyer’s word, for the pre-emptor is the claimant and the buyer the defendant. Some of the Successors held the opposite: the pre-emptor’s statement prevails, because the buyer has already acknowledged that pre-emption is due to him yet now claims an additional amount which the pre-emptor has not admitted.

Among Mālik’s followers there is also disagreement. Ibn al-Qāsim says the buyer’s word prevails provided he produces something tantamount to an oath; if he does not, the pre-emptor’s word prevails. Ashhab says that when the buyer produces corroboration his statement is accepted without an oath, even in matters that would otherwise require one.

It is related from Mālik that if the buyer is a person of authority known habitually to inflate prices, his statement is accepted without an oath. It has also been said that if the buyer offers nothing resembling an oath, the pre-emptor is referred to the market value, and—so I understand—the same applies when neither party produces anything of that kind.

They further disagree when each side produces testimony of equal probity. Ibn al-Qāsim holds that the two sets of evidence neutralise each other, and one reverts to the default: the buyer’s word is taken, but he must swear. Ashhab, however, maintains that the buyer’s testimony is preferred, because it furnishes additional knowledge.