I'm the author. The post covers the seven sources of non-determinism in the spec. The one that surprised me most in practice: about half the tools I tested rege

I'm the author. The post covers the seven sources of non-determinism in the spec. The one that surprised me most in practice: about half the tools I tested regenerate the /ID array on every save, even when the spec says it should be stable. Happy to dig into any of the pipeline stages or the qpdf invocation sequence if useful.