We've screened the room light for this UR5e faceplate study and kept the exposure fixed, but a bright band still moves when the part is reseated, so I'm trying to get the holder and physical defect map checked before the supplier's scratch arrows become our training answers.
Did the holder comparison show two actual seats? I'd get that answered before buying more lighting. And ask quality about the marked areas on the retained faceplate, because repairing a holder won't explain how those arrows got there.
Yes, the locating shoulder was sitting on a removable shim left from another sample; tooling restored the intended support and the repeated seat is now consistent, while quality withdrew the two guessed arrows and identified a real edge nick for the next optical comparison.