That last loop, hadn't the watcher specifically told them that it was the final loop, that looping wouldn't work now that the demon king was aware of it?
To be more accurate, that was assuming that the demon lord was in full possession of his mental faculties and able to cast.
That genuinely doesn't appear to be the case right now, he's barely able to express a will at all, and it seems to be interpreted, or expressed, in very distorted ways.
I don't think he's even in a state to cast Cancel Code, currently.