A branch or separate office of a bank is a separate bank for the purpose of computing the time within which and determining the place at or to which action may be taken or notices or orders must be given under this chapter and chapter 3 of this title, except that service on the bank as garnishee shall be made pursuant to section 12-1577. The receipt of any notice or order by, or the knowledge of, one branch or separate office of a bank is not actual or constructive notice to or knowledge of any other branch or separate office of the same bank and does not impair the right of such other branch or separate office to be a holder in due course of an item.