It's all relative...

You first say 500 is connected to 70 in the +Y, then you say 70 is connected to 500 in the +Y.

500 CNoded to 70 is +Y is identical to 70 Cnoded to 500 in the -Y. What you did was flip over the restraint.

Think of it this way...

When you don't supply a CNode, the assumed "connecting node" is EARTH. I capitalize it because it is very big, rigid and unmovable. (Actually we default to 1E12 for stiffness and that's pretty stiff too.) So your restraint reports show pipe load ON EARTH (as opposed to the restraint load on pipe). Think of EARTH as the other end of the restraint.

Now you add a CNode. All response is now related to the CNode rather than EARTH. A +Y restraint can move in the +Y direction AS RELATED TO THE CNODE. If the CNode "wants" to move more in the +Y direction than the Node, the restraint will remain active. If the Node "wants" move more in the +Y direction than the CNode, the pipe will disengage from the support and lift off.

So you can see why your two methods of input are opposite in effect.

Whether or not you have a firm grasp of this concept, it is important to do what you are doing - review the results to make sure the response is what you expect and question the analysis if necessary.