Validity of agreement

Person A sell a 32 cents of plot to Person B on agreement made on 10 Feb 1982. B registered some plot on his name as per his amount. A sold the some plots to different persons in Aug 1982 and 1983 respectively. Person B went to court on 2 Feb 1985 on the basis of the same agreement for more land. Court serve a notice to A through a post It was rec'd or not don't know Postal recpt taken as evidence and verdict given by district court in favour of B on 31 Mar 1986 for registration before 15 Apr 1986 if person A failed the registration bal amount to be paid in court and register. A may failed B went to court obtain decree and got it registed through court in 1991. A sold out the land to different persons , those buyers also sent to some x y z again they sold to different persons. B never come to claim that plots Suddenly B came in July 2020 claiming plots with hook and crook. Now the number of sellers and buyers changed since 1982. What is legal validity of A What is legal position of present owners of x y z on plot if he goes to court