Can you advice because of this mistake will the salah become invalid?
I heard from some other imam saying this is not an issue if it happens unknowingly. Can you please advise?
بسم الله الرحمن الرحيم
If the order of surahs was reversed by mistake then the salah was valid without a doubt. The other imam told the correct ruling.
Allah knows Best!
Darul Uloom Deoband
This answer was collected from the official ifta website of Darul Uloom Deoband in India.