Budget update from held purchase order

Hi all,

We an an issue with update of the budget for a WBS element (transaction CJ31) .

The "normal" behavior of a budget ( SAP Note 339856 ) would be that the budget is updated with the amount of the held purchase orders.

However, it's not always the case.

For example, if the amount is decreased, the budget is not decreased.

I've searched through sapnote and through debugging transaction ME21N but didn't find something relevant.

Any idea ?

For information, we are currently upgrading from 4.7 (SP SAPKH47036 for SAP_APPL) to SAP ECC 6.0 (SP SAPKH60604 for SAP_APPL) and it happens on both systems.

Thanks for your help.