A strange thing is happening with this tractor. I adjust the mower height to get the blades level, but after mowing my lawn for an hour or so, I notice the right side of the mower (therefore the blade) has RISEN about 3/8 of an inch, giving an uneven cut. After the mower sits for a while, and I'm not sure for how long, but could be more than a day or two, the mower height returns to around my original adjustment. The adjustment linkage is pretty straignt forward, consisting of a J-hook and nut and bolt on the tractor that connects to the mower, and when the nut is turned, it raises or lowers the mower. Has anyone encountered this problem with this tractor?