Is it true that Abdullah ibn Umar used to repeat his prayers, and what were the reasons that led him to do so? Did anyone else do that?

It is not known that Ibn 'Umar used to repeat the prayer he had performed; rather, what is transmitted from him is the opposite. Sulayman ibn Yasar narrated that he came to Ibn 'Umar while he was in al-Balat and the people were praying in the mosque. He asked him: "What prevents you from praying with the people?" He replied: "Indeed, I heard the Messenger of Allah, peace and blessings be upon him, say: 'Do not pray a prayer twice in one day.'"

Scholars have clarified that the intent of the prohibition is that a person should not pray the obligatory prayer twice considering it an obligation. However, if the second prayer is a supererogatory (nafila) one or with a congregation, then that is not included in the prohibition, due to what was narrated from the Prophet, peace and blessings be upon him, concerning one who prayed in his dwelling and then came to a congregational mosque, that he should pray with them, and it would be a supererogatory prayer for him. Likewise, his saying: "If you remain among a people who delay the prayer beyond its time, then pray the prayer at its time, then if the prayer is established, pray with them, for it is an increase in good."

Accordingly, if what might be transmitted from Ibn 'Umar concerning repeating the prayer – if it is authentic – then it might fall under these permissible reasons for repeating the prayer.