After the effective date of this chapter, it shall be unlawful for any mortgage trust deed or land sale contract to contain a clause or statement that prohibits the owner from applying for the benefits of the deferral of homestead property taxes provided in this chapter. Any such clause or statement in a mortgage trust deed or land sale contract executed after the effective date of this chapter shall be void.   [PL 1989, c. 534, Pt. C, §1 (NEW).]