I spent a chunk of my career working on productionizing code from ML/AI papers and huge part of them are outright not reproducible.

Mostly they lack critical information (missing chosen constants in equations, outright missing information on input preparation or chunks of "common knowledge algorithms"). Those that don't have measurements that outright didn't fit the reimplemented algorithms or only succeeded in their quality on the handpicked, massaged dataset of the author.

It's all worse than you can imagine.