DFF setup encounters error in Self Service during work order creation

I created a DFF to explicitly define each material requirement during work order completion as consumables, spareparts, protective equipment or tools.

The DFF works fine using forms.

But when using the self service in creating a work order and defining the DFF, an error is issued while saving.

The error for the specific stock number says.. "This error with Inventory Item Id 424 received an error status sinse an unexpected error occurred in the material requirement while performing attribute defaulting."

Would appreciate anyone's help and advice.

Thank you!