Engine Mismatch

Detection approach

Engine mismatch detected via error stack trace format. The reported User-Agent claims one browser, but the JavaScript engine executes and formats errors like a completely different browser.

How this helps detect bots

This signal is assessed with other independent session, browser, and network evidence. A single anomaly is a lead, not a verdict; corroborating anomalies make automated traffic more likely.

Legitimate traffic to consider

Users running legacy compatibility modes, niche custom browsers, or user-agent spoofing extensions for compatibility.