SalesFormLetter_Invoice (Sales Order Invoicing) and PurchFormLetter_PurchOrder (Purchase Order Confirmation) classes does not pass of the conditions when creating run time tasks for multithreading. The main task also ends before the 'child tasks' are done prompting the next task in the batch to start running in parallel as the condition of the previous task being Ended or Error is met.

We ask the these classes get updated so that the main "parent" task either stays in executing until all "child" tasks are done and/or inherit the conditions setup in the batch job so that the next sequential task doesn't start executing in parallel.