(1) In no case shall the back assessment or reassessment of real estate constitute a lien on the real estate that has, by bona fide sale, passed into the hands of innocent purchasers, but shall be a liability against the person owning the real estate at the time of the inadequate assessment.
(2) The burden of proving a bona fide sale shall be upon the person owning such real estate at the time of such back assessment or reassessment.
(3) Subsection (a) shall not apply to property that has wholly escaped taxation.