Change Material Desc in PO when it changes in Material Master

Hi Folks

Issue :

We made change to material description of MAT1 on Monday . Now, we checked the purchase order that was created for this material before the description was changed . Now, if you go to the PO 'AA' in edit mode(ME22n), take of the material number, click enter, it will give you error to entre the material . Then enter material number MAT1 again and click enter. check the description that has populated now. It is showing the new material description of MAT1 from MAKT(MM03).now we tried same thing with PO 'BB'. It doesn't work.

Analysis " For PO: AA the PR: AA1. In this PR it had maintained Language as EBAN_SPRAS = EN. So in this case material description is fetched from the PR.

For PO: BB the PR: BB1. In this PR Language is not maintained. So in this case the material description is fetched from the material.

Query : How can we fix this to always fetch material description from material master ?Is there any configuration ? I tried to fix material description using BADI

ME_PROCESS_PO_CUST~PROCESS_ITEM but it does not update the material description even using the Set data method .

How can we always populate material description in purchase order from Material master only ?