Submitted status is a temporary status until the application receives the delivery report from the SMPP/HTTP vendor gateway. It indicates that, your message has been successfully submitted gateway end and the application is waiting for the delivery status confirmation from the gateway
However, in such cases SMS get delivered but due to not receiving delivery report from vendor gateway, in that case SMS status will remain in submitted status. Further regarding exact time for updating status , there is no fixed time limit as it is subject to updation from operator as well as particular handset itself.