Why is my To Do step not clearing from my Inbox once I have completed the task?

Certain costing allocation business processes will trigger a To Do task to appear in your My Tasks inbox (Ex. Assign Worker Position Earning Costing Allocation for FWS Overage).  When you complete that task, the inbox message does not automatically disappear from your inbox.  You need to manually clear it out of your inbox by clicking Submit within the task message.