Users are not able to change Assignment start date in Task assignment, even with no committed actuals it always defaults back to the task start date, is this a bug?
This is working as designed.The task start date defines the assignment to start on or after the task start date.One cannot really change the start date of the assignment manually on the UI, regardless of having actuals submitted against that task or not- it would always default back to the default task start date. However, the start date of an assignment can be moved forward by adding the required ETC(Estimate-To-Complete). ETC is nothing but the estimated time for a resource to complete an assignment. Start date of the task basically defines the date to start the task assignment for a resource.
For more information on ETC and info on how to setup a project visit the project management sections of PPM product documentation:-