Expand the WATER classification and expand LEG-3. Notice there is an Invalid Corner (missing fitting) as shown in the following figure.
In specification driven piping, the order of piping features is not sequential, and is managed automatically by Pro/ENGINEER Wildfire. Therefore reordering or grouping of piping features should not be done, as this will corrupt the piping assembly.
Use CTRL + Left Click to select the Invalid Corner in the LEG-3 node.