Is there a way to add a purchasing UOM attriubute on an already existing approved supplier list?

I get an error message when I try to add a Purchasing UOM on the attributes page of an Approved Supplier List.  It seems like I knew how to add this a long time ago.  The error message that pops up immediately upon entry of a Purchasing UOM says FRM-40654: Record has been updated.  Requery block to see change.  But no change is made.

R12.

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