Expenditures made, liabilities incurred, or warrants issued in excess of any of the budget detailed appropriations as originally and finally determined, or as thereafter revised by transfer as provided by this chapter, shall not be a liability of the municipality, but the official making or incurring such expenditure or issuing such warrant shall be liable therefor personally and upon his official bond. The governing authorities shall not approve any claim and the city clerk shall not issue any warrant for any expenditure in excess of said detailed budget appropriations as finally adopted, or as revised under the provisions of this chapter, except upon an order of a court of competent jurisdiction or for an emergency, as provided in this chapter. Any one or more of the governing authorities, or clerk, approving any claim or issuing any warrant in excess of any such budget appropriation, except as above provided, shall forfeit to the municipality twice the amount of such claim or warrant, which shall be recovered in an action against such member, or members, of the governing authorities, or clerk, or all of them, and the several sureties on their official bonds, and it shall be the duty of the governing authorities of such municipality, or the State Auditor, as the head of the State Department of Audit, or the director thereof, appointed by him, or any taxpayer of such municipality, to bring an action therefor through the city attorney, or any attorney designated and empowered so to do by a court of competent jurisdiction. Provided, however, that the term "budgeted expenditures" for purposes of personal liability of members of the local governing authorities under this section shall not include any unfunded liability for municipal employee retirement or pension funds. Nothing in this section shall diminish any responsibility of the members of the local governing authorities to fund any employee retirement or pension plans, or any liability as a result of any failure to fund such plans as otherwise required by law.