The ruling on one who prays witr with the imam and then adds a rak'ah to make his witr at the end of the night

Q: Some people, when they pray witr with the imam and the imam concludes the prayer, stand up and perform a rak'ah so that their witr is at the end of the night. What is the ruling on this action? And is it considered that they left with the imam?

A: We are not aware of any harm in this; the scholars have stated this explicitly, and there is no blame in it, so that his witr is at the end of the night.
It is true that he remained with the imam until he left, because he remained with him until the imam left, and he added a rak'ah for a legitimate religious interest so that his witr would be at the end of the night. Therefore, there is no harm in this, and it does not negate the fact that he remained with the imam. Rather, he remained with the imam until he left, but he did not leave with him; rather, he stayed behind for a short time.