If a lien provided for in this part attaches to an estate less than the fee, forfeiture of such estate shall not impair any lien as to material, appurtenances, and fixtures located thereon and to which said lien has attached prior to forfeiture. If a lien provided for in this part attaches to an equitable interest or to a legal interest contingent upon the happening of a condition subsequent, failure of such interest to ripen into legal title or such condition subsequent to be fulfilled shall not impair any lien as to material, appurtenances, and fixtures located thereon and to which said lien attached prior to such failure.
§ 71-3-1012, MCA