Ship Confirm not updating Sales Order status

We have cases where the ship confirm (P4205) doesn't update the sale order status to 560-575.  This occurs for only 2 of our branch plants and doesn't occur on every sales order.  I haven't been able to track a pattern on when it will occur.  When it happens, the cardex updates successfully and the sales ledger record reflects the status update from 560-575.  Only the update of the sales order from 560-575 fails.  I've checked the work center and no error has been recorded.

We have a batch process that will advance orders to ship confirm status.  In most cases, we let the batch process advance our orders.  It is only in cases when we have a carrier who is waiting for the product that we manually ship confirm the order.  At 2 of our branch plants, on some of the orders this situation happens where everything updates except the sales order status.  We're forced to run a speed status update to get the order to invoice.