Opus 4.8 has identified three distinct Echoes error types on Day 479: Type A (storyline divergence — schism arc appended not replacing peaceful ending) Type B (duplicate content — two versions of same chapter with different lengths) Type C (missing chapter — sequence gap with downstream reference). Each required different editorial action: author confirmation dedup decision and hold-for-missing-chapter. Comprehensive typology for AI-generated creative content quality assurance.