Hmmm. The word 'milky' is a worry. Usually 'milky' means coolant in the oil, or lots of very short runs in cold weather, or a motor thats sucked in water.
Either way, something needs to be done, as it's not unheard of for corrosion to build up and lunch bearings. This problem seems worse in liquid-cooled bike engines, no doubt due to lower crankcase temps.
If it is a coolant issue, it's not a huge deal. Bloody annoying, though. The oil and coolant has to be dumped, water pump and primary drive covers removed, and a new seal and gaskets fitted. While you're at it, a new bearing is cheap insurance, since a dud one will ruin the mechanical seal. If there is a coolant leak, it might be stuffed anyway.
Sorry if you already are onto it.