Key legal question
Whether tax assessment decisions issued after the assessment limitation period are void and thus cannot serve as definitive debt-enforcement titles.
Extracted holding
A tax assessment rendered after expiry of the assessment limitation period is not void, but merely challengeable; once final, it remains a valid title for definitive debt enforcement.
Extracted reasoning
A failure to consider limitation ex officio is an internal defect, not a particularly grave defect causing nullity. Nullity is reserved for exceptional cases such as clear lack of competence or gross procedural defects; legal certainty also speaks against treating late assessments as void.