Does it go away if you put the headlights on and go for a longish drive? (basically letting the headlight heat up its casing and dries itself out).
Mine used to do it and would go away when I did that, the issue was the pins on the connector to the headlight from loom were corroded and let water in, so took it off, dried it out, cleaned it and put a small amount of insulation tape around the connector block just to try and keep it out, along with reseating the rear cover of the headlight to stop that from fogging too and cured my problem!