Answer

“Coming simultaneously” is a state in which the cause and the effect operate at the same time. In principle, cause and effect are always simultaneous, as Aristotle already pointed out (otherwise there would be a moment when the cause exists and the effect does not). So there is no physical contradiction here, and it makes no difference whether we are dealing with entities or with ideas. The difficulty is logical, because there has to be logical priority of the cause over the effect. I don’t see a problem with such a situation arising between entities. Of course, this also depends on the different understandings of the law of “coming simultaneously,” but this is not the place to elaborate.