Can another person claim legal heirship and ownership of property?

Respected Sir, A person owned two acres of agricultural land until his death in 2004. After his death, another individual, claiming to be his son, converted the property into residential plots and sold one of the plots through a registered sale deed at the Sub-Registrar Office. A few years later, the plot was resold through successive owners. I would like to purchase the same plot from the current owner. There is no issue with double registration, and the Encumbrance Certificate (EC) is clear, as the chain of ownership is not in dispute. It has been more than 20 years since the property was first sold, and the death certificate of the original owner is available. Is it possible for someone other than the claimed heir to come forward and declare themselves as the legal heir to claim ownership of the property? Can the claimed heir create any problems in the future regarding this property?