Playing as the Union of Britain, I helped successfully invade and annex Austria, and bought the Montenegrin provinces off of Italy so I could release Montenegro as my own puppet. Thing is, after Montenegro was released, it had its generic policy decision events fire. On foreign policy it decided to align with Serbia and ally with it, which caused the Balkan League powers of Serbia and Greece (Iron Guard Romania lost the civil war) to join the Internationale. While I don't mind having more countries join the alliance, I'm pretty sure this is not working as intended.