Under regulations prescribed by the Secretary of the Treasury, a loss resulting from a payment related to redeeming a savings bond or savings note shall be replaced out of the fund established by section 17303(a) of title 40. A Federal reserve bank, a paying agent allowed to make payments in redeeming a bond or note, or an officer or employee of the Department of the Treasury is relieved from liability to the United States Government for the loss when the Secretary decides that the loss did not result from the fault or negligence of the bank, paying agent, officer, or employee. The Secretary shall relieve the bank, agent, officer, or employee from liability when the Secretary decides that written notice of liability or potential liability has not been given to the bank, agent, officer, or employee by the Government within 10 years from the date of the erroneous payment. However, the Secretary may not relieve a paying agent of an assumed unconditional liability to the Government.