I found an edge case when using this trait on a class that extends a parent class that implements getSubscribedServices(). The issue occurs if the parent dynamically determines the return value of getSubscribedServices() based on something in the child class (in my case, using reflection). It's fine if only one class extends this parent but when multiple do, only the first class registered in the container has the proper services. The next classes have the same as the first because of the static variable.