This seems to be a pretty new SPR: "Surface - Ruled - Perpendicular to Vector (Plane). The ruled edges do not lie in the plane perpendicular to the selected edge."

To test the problem:

1. Open the completed file Mixer Rear Housing_&.SLDPRT

2. Edit Ruled Surface1

3. Unselect all the edges and re-select them again. If you follow the instructions on the manual, step 9 and 10, you will select  edges from the solid body.

This is actually what's happens:

The solution is to hide the solid body and use the edges from one of the shut off surfaces:

Too bad this manual will not have a chance to be updated for 2017. Maybe the training team will put some pressure on the developers to fix the problem, instead.

Otherwise replace the instructions from STEP 9 with "Isolate "Shut-Off Surface1" body.