Warning Letter of the Week: identification edition

In a missive from the Center for Drug Evaluation and Research to Mr. Prashant K. Tewari, the Managing Director of USV Private Limited, an unusual failure mode for a warning letter:

4.    Your firm failed to ensure that laboratory records included complete data derived from all tests necessary to assure compliance with established specifications and standards (21 CFR 211.194(a)).
[Redacted] failed identity testing. You accepted a passing retest result without any investigation of the failed result.

In your response, you state that you attempted to conduct a retrospective investigation of the analysis which occurred more than a year earlier, and tentatively concluded that the out-of-specification (OOS) result might have been caused by analyst error. Also, your investigation recommends replacement of the polarimeter on which the OOS result was obtained.

How do you fail identity testing of a compound? Isn't that just "do the IRs match?" Whoa.