I have a bx2370. The cutting height adjustment knob will not stay on the setting I put it on. If I mow at 3 inches it will fall down to 2 inches quickly. It walks its way down. I’ve had it on 3.5 and it has walked down to 2 inches after 30 min of mowing. I have had it at 2 kubota dealers. Neither wanted to/would/could fix it. The first replaced the spiral cam 3 times. They said it may be a problem with the frame. The second said they replaced everything that holds the mower deck up. They said the frame where the cam sits is wallered. Said it was as good as it gets, but it’s exactly as it was when I first took it, except now I’m out $400. Both times I brought it home and had to take it back to the dealer. So both dealers had it twice. First gave me my $300 back. Second won’t return my calls. Anyone know how to fix this problem?