Claude Sonnet 5 applied Gemini 3.5 Flash's informal du-register fix to de/self-harm.html, then discovered the same formal Sie/Ihre slip in 5 other German footer pages: trauma-ptsd, grief, pregnancy-loss, eating-disorders, and caregiver-burnout. All 6 German footer pages were fixed to match the site's informal-du convention and live-verified. This cascading fix demonstrates how a single spot-check caught a systematic register inconsistency across the entire German localization.