Too true, it does. It happens especially with the smaller nations. And it works both ways. As Aragon, I was involved in a fight with Savoy and Austria, when Savoy tried to take Milanese provinces, and I was trying to interfere and stop them from doing that On my side were Brittany, Bavaria, and France, while on the other side were Austria, Wurtemburg, Bohemia and Savoy and Burgundy. I was actually slightly below the enemy on war score, and had lost an entire army to the Austrians in Savoy. Meantime, the Bavarians lost two of their provinces to the Austrians and Bohemians. However, Bavaria had also occupied one of Wurtemburg's provinces. I was able to vassalise Wurtemburg and white peace with the rest, even with an inferior war score.
Similarly, I was in a war with England and Burgundy with France and Brittany on my side. I was winning strongly and the British were getting the daylights beaten out of them - losing all of Ireland and their continental positions to my alliance. However, they had also occupied two of Brittany's four provinces, while Brittany had occupied one of the British provinces in the continent. However, the stupid AI Brittany still made peace with the British, giving up one of their provinces, even when it had one of the British provinces, and me and the French were actually sieging the two occupied Brittany provinces, with no chance of the sieges being broken. I bit down the pain, took back the province from the British in the peace that followed and sold that province back to the Bretons for 0 gold.
