What is the ruling on a person accused and proven guilty of apostasy who subsequently denies the apostasy?

Primary text

If a person is proven to have committed apostasy by the testimony of valid witnesses, and then denies this apostasy, their denial is not accepted. They must be asked to repent (istataba). If they repent, they are spared; otherwise, they are executed. The evidence for this is the narration from Al-Athram, via his chain of narration from Ali (may Allah be pleased with him). When a man who had become a Christian was brought before him, Ali asked him to repent, and when he refused, Ali executed him. Furthermore, a group of people praying, known to be heretics (zanadiqa), were brought forward, having been proven so by reliable witnesses. When they denied it, claiming their only religion was Islam, Ali executed them without asking for repentance, stating that he only asked for repentance from the Christian because he had publicly shown his previous religion, whereas the heretics were executed because they denied the established proof against them. Since their disbelief has been established, their Islam cannot be ruled valid without the declaration of the Shahadatayn, similar to an original disbeliever. Their denial is also a falsification of the evidence (Bayyinah), thus their denial is not heard, like in other claims.