I am not sure what you mean here. Is it coup related? Can you make a proper bug report with repro steps and saves in the bug report forum
The problem is that, for example, the British declare war on Yugoslavia. The latter enters the Axis. A few days later, as I understand it, a bug occurs, Peter replaces Paul and the country falls out of the Axis while being at war with the Allies. Is not this a bug?
The Yugoslav confederation does not appear in this case. Although the national spirit of the military against Germany is present.