Tonioz said:wrong province can be demanded, if you manually drop something from list, and it starts to bug.
HAL, we will make exchange then after your inherit Lith
KJ, what Tonio says here is right. It has happened to me a number of times in MP. It is very frustrating. More exactly this is what happens
1. You open up the peace screen
2. You select a number of provinces you are going to ask for
3. You determine that it is too much (say e.g. the WS sum you demand is larger than your actual WS and thus it will not be a stab hit)
4. You decide to lower your demand and you do that by clicking away a province
5. You then send the offer and let us say it is accepted
6. To your horror you now see on the screen a message saying you got this province you clicked away and instead lost another one
I do not know if, when you click away the province, the display show the ones you have selected or the ones you will eventually get when you send the proposal and it is accepted. If the latter than you have at least a chance to understand something has bugged, if the former you are chanceless