My nomenclature was confusing. Let's simplify further.

You have a system that consists of nodes 1010 thru 1040.

1020 is a bend in the horizontal.

nodes 1010, 1030, and 1040 are guides with vertical supports, and let's say guides with gaps, because it's easier to visualize.

It also consists of unknown piping from nodes 10 through 1000.

There's a pipe routing between 10 through 1000 that, with friction, you do not see contact the guide at node 1040, but you have friction loads in the positive direction.

That same pipe routing, same temperature, without friction says that at node 1030 you contact the guide and have moment reversal, and then at node 1040, you see the pipe move in the opposite lateral direction and contact the guide and have contact loads in the negative direction.

+500 vs -1000. The force due to friction at node 1040 is not (+)500 - (-)1000 = 1500. No - the force due to friction is clearly simply 500.