Have quality judge that cover against the appearance requirement first, with its identity tied to the images; the shifting highlight can remain an observation without becoming a defect label.
Keep the eventual operator in the reference handover too, so the decision does not remain something only the person who organised the photographs understands.
Use accepted and genuinely rejected covers for the later presentation comparison, including difficult normal reflections, rather than testing only whether this one bright line disappears.
Farah, that also makes the handover easier: the operator can see an accepted awkward example beside an actual reject, with the physical decision explained.