Truck moves forward in neutral when cold.

So this morning it was cold enough that I had to scrape the windshield.
I started the truck put it in neutral and got out to scrape it and the truck is rolling forward! Of course I did not have the ebrake on and yes it was parked on a flat surface. I pushed the clutch in and it stops rolling.
Let the clutch out and it starts moving forward. Is this a sign that I need to adjust the clutch or is my clutch failing?

Thanks for any help.

2002 V6TRD 4WD Manual trans.

 

Mine does the same thing when it's cold.

 

Wtf. How?

 

Seems to be pretty common for manuals in cold winters, Some say it's just the viscosity of the oil used. Maybe flush the trans and replace with some MT-90