What is the ruling on one who performed Umrah on behalf of his deceased maternal uncle after performing the Hajj obligation and before the Farewell Circumambulation by one day, and does this entail any defect or error, and what is its rectification?

The flaw is that the maternal uncle performed ihram (definition) from Tan'im on behalf of someone else. What is obligatory is for the proxy to enter ihram on behalf of another from the miqat (definition) considered valid for his madhhab (definition). It is safer to rectify this act by offering a dam (sacrificial animal) to be slaughtered and distributed among the poor of Mecca, while emphasizing the obligation of performing the Farewell Tawaf (definition) before leaving for the miqat to enter ihram.