That is more than likely trapped condensate. Ride the bike for a bit, then look at it again. It shouldn't look milky after that, as the moisture will have evaporated. It's a common thing to happen in the warmer months when humidity rises. Nothing to be alarmed about, unless it doesn't go away after the engine is fully warmed and the oil has circulated. A 30 minute ride should be plenty to clear it up, but you'll more than likely see it again.