If they changed the policy such that deadheading flight attendants are above eUps (and assuming this FA was deadheading), then yes, an eUp opportunity was lost due to the change.

Prior to the introduction of PY, an SEMM in Y was pretty much guaranteed an upgrade. Then along came PY, and an E50K in N had higher priority. It was a change that resulted in people sitting in Y who previously would have received the upgrade.

It all comes down to priority, and this priority has clearly changed.