At the last moment the exhaust turned green. That's consistent with the fuel running out, the engines running oxygen rich, and subsequently "engine rich". So I would put my money on actually running out vs a measurement error.
And even if they had caught it it wouldn't have been worth much as the expensive part is the engines and they wouldn't have been reusable.
And even if they had caught it it wouldn't have been worth much as the expensive part is the engines and they wouldn't have been reusable.