upon the right has been vested into the successor gen.

[Larisochka]

Подскажите, пожалуйста, здесь имеется ввиду : ..upon the right has been vested into the successor( до перехода права правопреемнику)?
Контекст ниже:

This Agreement shall bind the statutory heirs, executors, successors, guardians or legatees of the Buyer, however, such successor must notify the intention of succession to the Seller within 60 days from the death of the Buyer or upon the right has been vested into the successor otherwise it shall be deemed that this Agreement is terminated which the Buyer shall not make any claim against the Seller.

Заранее благодарю за помощь

[AsIs]

после
(60 дней ... с момента перехода)