GPA Holder and Agreement to sell holder different

My mother purchased property in october 2005 in delhi on GPA and agreement to sell. The original party was Mrs R and she did registered GPA to Mrs A and executed registered agreement to sell for consideration to Mr B(who is husband of Mrs A) and registered will was also executed by Mrs R to Mr B too. Now Mrs A executed registered GPA to my mother and Mr B also executed registered agreement to sell and registered will in favour of my mom for consideration on sane day in front of registrar. Now my mother went to Land and development office in delhi to get property freehold. L&DO officials are saying that these papers are wrong and Mr B cannot execute agreement to sell and a rectification deed is required where Mrs A becomes 1st party and my mother second party and Mr B need to become confirming party. Please suggest if this is ok and should be done or not as deed writer suggested that papers are correct and no need for rectification deed since Mrs A done GPA who was GPA holder to Mrs R and Mrs R did agreement to sell to Mr B who is agreement to sell holder as Mrs R can do GPA and has right to sell too... Please suggest