(a)no claim that such partial partition has taken place shall be inquired into under sub-section (2) and no finding shall be recorded under sub-section (3) that such partial partition had taken place and any finding recorded under sub-section (3) to that effect whether before or after the 18th day of June, 1980, being the date of introduction of the Finance (No. 2) Bill, 1980, shall be null and void;