[Is evidence accepted after the two disputants have been “restricted” (taḥjīr)?]

The answer: There is no objection to accepting evidence after taḥjīr, and the other party has the right to counter that evidence.
The proof of that is that the intended purpose of appointing judges is the establishment of truth and fairness among people, and evidences are among what makes the truth appear and clarifies it. It is not permissible for the judge to reject something by which the truth becomes clear to him; otherwise, he would be turning away from judging according to the truth.
And taḥjīr means that the two disputants have completed what they have of claims, responses, and proofs, and that they have given the judge permission to judge. So if one of the two disputants presents to the judge evidence after that, but before he has passed judgment, it is upon the judge to accept it, and upon his opponent to counter it.
As for when the disputant brings his evidence after taḥjīr and after judgment has been given on the basis of an oath, the scholars of the madhhab have said, in meaning: If it was the disputant himself who requested the oath from his opponent and said to the judge: “Let him swear for me, and I am satisfied, content, relinquishing [my claim],” or similar words – then the judge made him swear, and wrote the judgment of ownership for the one who swore, on the basis of the disputant’s request for that – then, after that, the disputant’s evidence is not accepted and is not heard.
But if it was the judge who obliged the denier to take an oath and demanded it of him, then he swore, and after the judge made him swear he ruled that ownership was his, and then after that the disputant brought upright evidence – then it is obligatory upon the judge to accept it, and to oblige the one who swore to listen to it and to answer it. If he produces something that undermines it or counters it, then so be it; and if not, then it becomes obligatory upon the judge to rule according to it and to overturn the first judgment. Thus have the scholars of the madhhab said.

Source: Min Thimār al-ʿIlm wa al-Ḥikmah vol.2