The Planning Board, after adoption at a Town Meeting of any Zoning Bylaw or amendment, shall furnish a statement and pertinent maps or plans explaining said changes to the Town Clerk for submission to the Attorney General. The effective date of adoption of, or amendment to, any Zoning Bylaw shall be the date such adoption or amendment was voted on at the Town Meeting. If said bylaw shall be disqualified by the Attorney General, the previous bylaw or portion thereof shall be deemed to be in effect from the date of said vote.