At first glance there exists a tension between the capitalist state and the capitalist class itself. When cases of corruption blow up, it isn't uncommon to see other parliamentarian actors appealing to nationalism, "the common interest", which the parties involved have betrayed, establishing implicitly a need for the capitalist class to first look out for national interests, not their immediate individual or supranational interests. The knights of national pride won't waste a single day going after the excesses of internationalist monopolistic competition when they stand to gain favor in the eye of their support base. It is never more seemingly apparent than when it is a member of the state administration also a member of the capitalist class itself, and rules for their own interests.
But it is better to take a step back and not lose oneself in the form and individual actors that play in these examples. The capitalist class is a heterogeneous one, with multiple internal currents corresponding to the possibilities for the direction it can take collectively, superstructurally manifested in the wreath of parties and ideologies who bid for their turn administering the economy in this or that direction. What is beneficial to one current might be detrimental to another, and in practice, such as in the immigration debate, or the degree of worker's protections, or the status of women, represent actions that are beneficial to the capitalist class in general at different times of its anarchic development. Sometimes it is beneficial to integrate more migrant working force into the economy, others it is beneficial to shutoff the influx and even reverse it. Depending on what part of the recession-expansion cycle an economy is on, expanding worker's standard of living or constricting it is more or less beneficial, possible or impossible.
Next, the state is an instrument of class oppression, it serves no other primary purpose but to contain class antagonisms from class warfare, maintaining its eutaxy. Its jurisdictional coincidence with a nation is a mere product of the historical development of the state itself under capitalism, not a necessary or original condition for its existence, and given the actual porousness of a nation, the borders of a state never actually even fully coincide with those of a nation, which by its nature as a social entity non-physically linked to the territory, lacks actual concrete borders. The identification of the state with a nation is a rhetorical one, first and foremost, itself reliant on the presupposition that a nation even contains a common set of interests in class society. So then, what is that apparent tension?
It's less of a tension and more of an imperfect coupling between the capitalist class and state. We've recognized that the bourgeoisie is heterogeneous and contains more than a single program for its own prospects. Applied to the state, this means more than one approach to handling it, its component institutions and rules for its tasks, duties and chores. In general, different approaches for the political, social, cultural and economic dominance of the bourgeoisie. When different capitalist currents butt heads over this matter, they naturally recourse to presentable arguments (whatever is presentable in a given state during a given time!), such as those of patriotism, or of social equality, or of humanitarianism/human rights, or of military force, so on and so forth. The tension exists between the various factions of the bourgeoisie, who might veil this substance in the form of arguments which appeal to the state as it is identified with the nation (or other categories such a race in most kinds of fascist movements). The state can only serve one master at a time, however, and instabilities might present themselves when these intra-capitalist tensions go beyond their mundane parliamentarian diatribes and good civics.
This might seem like splitting hairs, but under the first observation, one which was the starting point for myself, lies the conclusion that the state possesses an inherent character distinct from that of its class administration, this difference being the source of the apparent tension. Do not be mistaken, the state is an apparatus of class domination that only exists for as long as there are classes, and has served many previous masters before our own, slavers and feudal lords. And when it serves the proletariat, a state constructed for own purposes and not simply adapted from the capitalist state (the ready-made state machinery), it will do so for as long as the will of the proletariat is sufficiently united, the same condition every other class in history has had to contend with.
Going back momentarily to the arguments about "patriotic capitalists" I referenced at the start, there is, in fact, a tension here between the capitalist class and the nation, but the mistake comes from assuming the state is what personifies the nation. A nation has no common interests as long as it is internally divided along class lines. A Spanish capitalist is first a capitalist and second a Spaniard, whose economic interests will guide them through a path that may at times aling them with "Spain"'s "interests", and at other times put them at odds. A Spanish worker is first a worker and second a Spaniard, whose economic concerns are essentially identical to those of a French or Moroccan worker, inter-state dynamics notwithstanding. It is only in a classless society that can a nation be said to have common interests, because it has been united beforehand on a common productive ground. A corruption case is nothing more than the mundane relation of subservience of the state to the capitalist class being twisted for the benefit of a smaller portion of that class.