The issue can be replicated in the OLAP and KPIs Support demo.

Steps to replicate the issue:

• Add an item to the "Row Fields" by checking the checkbox of the item in the "All Fields" panel
• Remove the item from the "Row Fields" by unchecking the checkbox of the item in the "All Fields" panel
• Click the Update button
• After the PostBack the PivotGrid will display the Item in the "Row Fields" despite it was removed soon after adding it.