A very late reply to your problem, but I just ran into the same problem and found a solution for it. In one of my fittings the line for the tube didn't go through the route point. It started at the connection point, but then missed the route point by a fraction. Invisible if you don't know what you're looking for, but it caused the problem. I opened the tube sub-assembly in a separate window and gave the line and the point a coincident constraint. That fixed it!
SW routing has the most convoluted and useless workflows for hydraulic and pneumatic tubing.