Getting error message " Total Release Quantity exceeds maximum quantity on sales agreement line"

Hi,

I am getting the error message on sales order form " Total Release Quantity exceeds maximum quantity".

We have created a sales agreement for an Item. After that, we create a release against this agreement and then this release is processed to Ship confirm. The status on the line shows "Shipped". After that, we have create another line for return of some quantity with negative sign and provide a reference of sales order on this line. RMA  process completed through receiving and line shows the status "Returned" but in shipped quantity field the quantity displayed with positive sign. After that we have created another release against the agreement with the same quantity which we have returned on