Don't remember last fall when I took it off. However it seems it did go down to remove mmm.
Just to confirm. You refer to the issue in this post in the singular. Is the issue with TWO tractors, or just one?
If only one tractor, try setting the mower deck position knob at each position 1 and 4 and see if it makes any difference. (using my memory, I think the high is 4 and and 0 is the low, so 0 is between 1 and 4) What I mean is set the adjustment at both sides of the minimum and see if that makes a difference.
There is a disk on the shaft of the height adjustment knob, that essentially has a different thickness for each position, and this thickness sets how much the deck will drop for each setting. IF it shifted, this could cause your situation. You CAN solve this issue! It is not a rocket science setup.
Edit: I meant IF the disk shifted the old zero could end up now being between numbers on the knob...I do not even remember if there is a zero setting, probably not. But if the disk on that shaft shifted, the net result woud be the same. Shifting can only increase the stopping distance of the lowering function, regardless of the numbers involved.