That's just the way they are. A set of limit chains can help a little but they require a lot of fiddling each time you want to change the height. One thing that can help a lot (Zane or Hokie-style live hydraulics, which let the hydraulics operated independently of the PTO but cost $500 or so aside) is the Implement Transport Lock Ford (or was it Ferguson?) used to make. It's just a little strut that goes on one of the lift arm pins, and can be swung in so it sets atop the axle housing, keeping the arms from settling when the PTO is disengaged, so as to hold the implement in the transport position (that is to say, up). A spring loaded block off keeps it from deploying when not desired.
Red Rock makes a copy of the original but it is possible to make a simplified version very easily.
I don't often see these on n's, don't know why, as I consider mine indespensible.