混合文本/代码/屏幕截图 PDF 中约 14% 的页面发生静默图像丢失 - 没有错误或日志输出

Minimal, fully-synthetic reproduction — root cause identified: A single-page PDF with real PDF text (title, two body paragraphs, a "Figure 16:" caption) plus one embedded raster image between the paragraphs — the image is a synthetic "code editor screenshot" (dark background, colored monospace-style text, 400×240pt) — reproduces the defect exactly: the surrounding text and caption extract correctly, but the image is dropped entirely (no exported file, no reference in the markdown).