Why Valid EPUB 3 Crashed Amazon KDP: Engineering an Automated E-Book Compiler

When our technical manuscript passed W3C EPUBCheck with zero errors, we thought we were ready to ship. Then Amazon KDP crashed with an opaque internal server error. Here is how I engineered an automated Markdown-to-EPUB 3 compiler, tackled KFX text-shaping bugs, native MathML, and turned ASCII architecture diagrams into responsive vector assets.