Ref. No. 244945-3709
In the name of Allah the most Gracious the most Merciful
The answer to your question is as follows:
A Musafir Muqtadi will pray full namaz behind a Muqeem imam and it is not permissible for him to do Qasr. The said person does not know the proper ruling of namaz . The one, who has shortened the prayer behind the muqeem imam, is obliged to repeat the prayer, and in such a case he will do Qasr while repeating the prayer.
And Allah knows best
Darul Ifta
Darul Uloom Waqf Deoband