A number that could not be true
A live answer showed WTI crude above Brent, both as current prices. WTI trades below Brent. Both figures were real. One was a historical peak presented as today.
On a trust product, accuracy is a release gate, not a quality metric.
The fix
A fixed consistency check now runs after writing and before release. On a flag the answer is discarded and the last good result is served, clearly labelled.