BP Master Data - 'ID No. 2' field is not editable for a specific user

Hi, 

The contented hap to this circumstantial user, the user  has afloat authorization for concern spouse maestro data, however, the tract ‘Company Reg No’ (original sanction of this tract is 'ID No. 2') is not editable. This hap to each BP types, whether is Add oregon Update mode. There is nary UI configuration successful the BP maestro data.

I person tried login utilizing this affected user, spell to edit UI configuration, and tried 'Restore Default' UI, but nary help.

Any idea?

Phoebe