How is a dispute resolved when the parties disagree on the time an existing defect occurred?

Primary text

If the parties dispute the timing of a defect, and the nature of the defect permits only one of their claims to be true, the statement of the claimant is accepted without an oath because an oath is only used to resolve ambiguity, which is absent here. If both claims are potentially true, the ruling follows the dispute over the timing of a defect in the sold object. One view, held by Abu Hanifa and Al-Shafi'i, accepts the statement of the pledgor because the basis is the validity and binding nature of the contract. The opposing view accepts the statement of the pledgee, following the legal principle applicable to sales where there is a dispute over the delivery of a lost part, as the pledgee is denying the delivery of that missing part.