First year we were here my neighbor that plows our roads told me about this happening, I thought he was goofing on me & chalked it up as an urban legend....
It happens alot, especially on plow trucks, where the blade will sink down in and then freeze several inches into the ground. Makes it a royal PITA getting the truck moving. Even the force of the hydraulic cylinder can't overcome the grip of the frozen ice & ground. So you have to rock the truck to break it loose.
Leave the plow up, destroy the suspension... put the plow down, have it freeze in the ground (along with your tires on occasion).. :D