Property Related

Landlord having 45% share has transferred his rights of sale to a third person who is not a relative nor a builder agreeing to sale/ receive proceeds out of the sale to a GPA holder and such GPA has been executed on a stempa.parer of Rs 3 which is duly registered and stamped in the registrar office. Now a sale made by GPA holder to a purchaser is a valid sale or not and will there be any title issues if a transfer is made only by GPA holder without signature from the landlord. Please clarify