View Submitted Tasks is showing a Task as completed while some of the events in the Task are still in progress or not yet initiated.
This is functioning as designed.
Only the Primary and Secondary Events generated from the original task are tracked directly. Once the Primary and Secondary Events within the Task complete, the Task itself is considered complete.
An Email Event is not generated by the original Task, it is generated by another action elsewhere within the Tasks' processing and therefore not considered part of theoriginal Task as far as the Tasks' completion status is concerned.