Cannot change the planned end date of closed task

[sigmachiuta]

I have created a project template and applied it to a project with automatic calculation (also tried with manual).   Even when i start the project today in the planned start it gives me these errors when closing the task.   The unusual part is that it actually does close the task and change the Planned end date and planned start date and actually closes the task out.   Confused on why it would throw the errors but still update the record.   and why am i receiving these errors

Cannot change the planned end date of closed task

Cannot change the planned start date of already started / complete task

Invalid update

[Manikandan T]

Wbs it creates empty while project task   creating through the workflow   .it is not viewing .manually creating a record it show in the columns