The PDF viewer uses 1-based currentPage (starting at 1) but the OCR engines produced 0-based pageNumber from enumerate(). Annotations created by OCR were assigned to page 0, which doesn't exist in the viewer. Change enumerate() to start=1 in both engines and the streaming endpoint. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>