I went to war with an opponent. This opponent was another civilization's vassal. That made the suzerain attack me. However, I couldn't counter attack the suzerain, I was stuck at 50 war desire, and unable to attack any unit or city, with the same message you see when you are at peace with not enough war desire to enter war (Cannot be done as you have to declare war and don't have enough War Desire for that). When I went to the diplomacy screen, the status was War.

The war with the vassal worked as intended.

That means I just got absolutely destroyed, because I couldn't do anything so I just entire portions of my empire helplessly, while being much, much stronger than him. This is clearly a gamebreaking bug.

Hi Endyron!

Do you happen to have a save for this? If so, could you attach it? It would be located in:

C:\Users\<users>\Documents\Humankind\Save Files