I've had some crashes with a pdf scan I made myself, but I couldn't detect a pattern and it was the first time, so I'll observe it a bit further. However, when I started to read this pdf from archive.org (cleaned up and OCR'd by myself), reading in landscape mode was impossible because of too long lines) and when I switched the reflow on, it was like a miracle, and I don't think any other reader can perform this: Reflow in the original font, portrait mode, and the images resized to fit the screen width!