IIRC they don't, but as someone who doesn't know Erlang, the Erlang documentation was really hard to read and the APIs differed from other Elixir libraries.
Imagine it's an important lib you can't just replace and there's a bug you need fixed and can't just wait for the maintainer to do it for you. Now you suddenly need to understand that language enough to do that. To some extent this happens very often, I've had it in Clojure+Java and PHP+C libraries.
Exactly the problem I've run into on more than one occasion. And the erlang libs I'm referencing have almost zero documentation, so it really means "RTFC" which then is painful :D