My old failure examples lack a useful denominator, but this FR5 fixture review has another problem: two revisions beside one final reading. Which setup produced it?
Is there a bracket identity you can follow through the original sheets? The summary may have combined two examples. I would check that before trying to explain the released dimension.
Then that example cannot settle the fixture comparison yet. Keep it marked uncertain and ask for an identified current observation under the intended setup, rather than choosing whichever old revision fits the story.