Haxe compiles to a lot of languages. Some of those language targets are better maintained than others. I've definitely had situations where some usage of esoteric Haxe features (like, deep/complex generics alongside runtime polymorphism) compiled fine to one target but compiled to invalid or incorrect code on another.

(Interestingly, in my experience the C++ target is rock solid. Though that experience is from many years ago.)

In any case, the best source for known compiler bugs is always gonna be GitHub:

https://github.com/HaxeFoundation/haxe/issues?q=is%3Aopen+is...