Wrenfield Veterinary Group's specialist compares two Testing Center batch runs a month apart on the same 50 test cases and notices the pass rate dropped from 98% to 88% with no configuration changes made in between. What is the most defensible next step?

When the test cases and the agent's own configuration are unchanged but the pass rate drops, the cause lies in something else that changed underneath: a Data Library source that was refreshed with different content, a retriever reconfigured elsewhere, an underlying model or platform update, or a data change in a referenced record. The defensible move is to investigate what actually shifted in the environment or dependencies rather than assume the agent's authored configuration is the culprit when it provably didn't change. Declaring Testing Center itself unreliable throws out a validated tool based on one anomaly without investigating a more likely, specific cause. Rolling back a full year without diagnosis is a drastic, disproportionate response that could undo a year of legitimate improvements to chase a problem that might be a single misconfigured Data Library refresh. Dismissing a 10-point drop as still 'passing' ignores that this exam's domain repeatedly emphasizes catching regressions early — a meaningful, unexplained drop deserves root-cause investigation, not a shrug. The exam expects specialists to reason from what changed, not from assumptions.