Anyone know how to figure out which route stubs are created in the wrong direction?

I've got an assembly with a bunch of imported (Swagelok / McMaster-Carr) part models, and got everything set up roughly where I want it. I've created route points at all the tube connection points, and from the little arrows they all appear to be going the right direction (outward from the fitting, right?). However, once I sketch in the tubes themselves and exit sketch mode, a couple of the tube sections disappear. When I select Edit Route to see what's going on, I get the message "Some of the route stubs have been created in the wrong direction and must be corrected manually to fix the problem permanently."  But, there's no indication of which stubs it thinks are in the wrong direction. All the arrows still appear to be correct, and I've tried deleting and recreating the route points that appear to be affected (ie, their tube disappears), but it hasn't helped.