storage location defaulting in PO

Hi Experts,

For one of the user the storage location(wm storage location) is defaulting when she tries to convert a Purchase request to PO via MD04(stock requirement list). i checked the PR and there is no storage loc maintained there, next i checked her personnel settings in PO screen and no defaults maintained for storage loc , then i checked her user profile for parameters and no default values exists for storage loc. i checked the material master for that particular material and storage loc is not mentioned.

any idea why the storage location is defaulting? what else do i need to check??

Thanks

Mahendra