Lock date not working for inv.items & delivery note

  1. Generated DELIVERY NOTE from inventory items list for sales with
    date 18/03/2020
  2. New account year entered as 01-04-2020 to 31-03-2021
  3. After editing same item with new sl no details in
    inventory list found, locked DELIVERY NOTE details also edited

any one can help,what could be problem


lock date is to prevent modification of transactions prior to a set date.
it does not prevent modifications of master data like inventory items, customers, suppliers, etc.
so editing these will change the same appearing in relevant transactions.

Thank you