Resource Assignment deleted from the service order

Hi,

I use resource planing on CRM 7.02 and I am facing the following problem:

- sometimes (I wasn't able yet to simulate the issue but this happens in my production system) the resource assignment selected on a specific service order item disappears after saving the document.

The date "Earliest Appointment Start" from the item continues with the value from the resource planning assignment, but the assignment itself is deleted from the document. And after this the user can select the same day/hour in another service order.

Can anyone help me on this?

Thanks.