There is a tool for Skyrim that lets you strip and clean orphan scripts (left over, save bloating garbage scripts) from save games that once had mods that were deactivated. I'm not sure how the PZ saves work, but could there theoretically be a way to do the same for PZ saves? Or would it be impossible? Regardless, it might be worth looking into when PZ updates, mods get left behind in the dust and leave behind important things that end up destroying your save game. Let's avoid that, shall we!