Public Record bedroom number is different than the advertised bedroom number

Public Record bedroom number is different than the advertised bedroom number.
For instance, Public record and tax assessor says 4, while advertised bedroom number on MLS/listing is 5.

The listing agent insists that the bedroom number is correct and that assessor and public information are wrong.

What steps do I need to ensure that the advertised bedroom number is correct?

My concern is that they added a room without permit(Not permitted work).