According to this article, Romanian Constitutional Court decided upon a notification coming from a parliamentary party regarding its own members immunity. Shortly put, they are deciding the constitutionality of some laws related to them.
According to Britannica, checks and balances is:
principle of government under which separate branches are empowered to prevent actions by other branches and are induced to share power. Checks and balances are applied primarily in constitutional governments. They are of fundamental importance in tripartite governments, such as that of the United States, which separate powers among legislative, executive, and judicial branches.
So, according to this principle, checks and balances does not seem to apply when it comes to some of the Constitutional Court's decisions (those involving Court's members).
Question: Does Constitutional Court deciding upon a law related to its members break the "checks and balances" principle?