Customer Material number not copied into sales order !

Hi folks,

I'm after data migration phase from legacy and post-Go Live for an implementation of ECC6.

Whereas CMIRS have been successfully migrated, the customer material number is not copied into new sales orders (VA01). I checked Sandbox environment, Dev and Qual, it is all working fine, except in production.
I check VD52/3, all is OK, I checked VOV8 (maintain doc type), the checkbox "copy from info record" is checked.

Any suggestions on how to set that right ?

Thanks

Charles