250-500cc WR300 Water in the oil?

I just changed the oil in my 09 WR300. When I dropped the old oil, it looked kind of milky, so I decided to cycle the oil through one time. So I filled it, ran the bike for about 1 minute, then dropped the oil again. This time the oil was completely white with water.

I cycled the oil again with the same process, and this time the oil was still milky, but not as bad as the prior oil drop.

If this was a 4 stroke I would suspect coolant in the oil from a leaking head gasket or something, but is there any path through which coolant could get into the transmission oil of a 2stroke? I had the bike stored outside for 2 weeks because my car has been inside the garage being worked on where i usually keep this bike. Is there any way rain water could get in the transmission?

I change the oil as frequently or better than the manual suggests, and use Rotella 10W40. The bike has no leaks of oil, so there are no holes or cracks in the cases as far as I know.

Any idea what could cause this problem?

Bad water pump bearing or seal I'd say.

Curious, how did you get this fixed? Was it the water pump bearing?
I think I might have this same issue (definitely have coolant in my transmission oil) and looking for more info on how to fix it.
I have a 2008 WR250.