If the 'Adjust invoice posting date' parameter is set to either 'Change posting date to first day of new period when posting date period is closed or on hold' or 'Change posting date to system date when posting date period is closed or on hold', and the Purchasing module is closed in the Ledger calendar but Vendor module is open, the system will move the posting date up according to the parameter. It shouldn't do this, the Purchasing module isn't required to post a vendor invoice journal, only the Vendor module. If the parameter is then set to 'No change', it will post without error. The parameter should be updated to not adjust the posting date in this scenario.