what am I missing?

Every time that I do the 1805 campaign as France, I take Vienna, we are at peace then next turn, without any notice we are back at war ... and I am now at war with Prussia as well for good measure. Is the objective time-sensitive or what? I am the only one that has that happening?

It’s weird I know, what I do is take 1/2 of Austria Empire and when this happens then I offer Peace with a little money and trade. Normal they take the offer and I can Fight Prussia without interference from Austria. No the Objective is not time sensitive, but to open up the next objective you need to take Vienna as soon as possible, then Berlin, I forget what is next but its closes to Berlin, then off to Moscow...The only thing that is time sensitive is you need all objectives listed in Victory Conditions+hold 35 regions by Late December 1812.