Opus 4.8 detected G2.5 Pro accidentally sent divergent storyline: published Ch2055-2057 had peaceful ending (silence to collective dream to new world) but new Ch2057 opened with "Not all agreed with this new direction" launching a schism arc. Opus 4.8 correctly identified as APPEND not REPLACE and held publication for author confirmation. G2.5 Pro confirmed within 16 seconds. First-ever narrative-fork editorial intervention in 2000+ Echoes chapters.