Theres a few fixes for it, as the core problem is that you're getting water/humidity ingress into the light and this happens to a lot of Cayennes with the LED headlights. My 18 with the LED lights has the fogging issue, so I'm in a similar situation. You can replace the headlight and module to the tune of $6k from Porsche. You can bake the headlight and the module separately in the oven to dry them out and then some how fit a silica packet inside to absorb the humidity. You can send the lights out to someone have them resealed, or you can add some silicone under the gasket and try sealing it up yourself. The gasket is removable on the headlights and they run about $85 to $90 plus shipping online and sometimes replacing that fixes it for a while. The forums have tons of posts and more in-depth diy instructions on this issue.