laravel/framework — pull request #3423 by anlutro (2014-02-01 07:53:45+00:00)
Title: [4.2] Don't allow relations to be accessed via snake case

This is just a weird inconsistency that will catch you off guard. If you eager load a multi-word relationship (using camel case function names of course) but access it via snake case, it will bypass the eager loading.

The alternative is to move the converting of $key to camel case before checking if the key exists in the already loaded relations.