Remember when the plumbing code update had a typo in the venting section? A buddy followed it and failed inspection twice. He wasted a whole week redoing work because of one wrong diagram. Training materials need to be double-checked before they go live. Mistakes like that cost time and money, and in your case, could be a real safety issue. It's frustrating when the stuff we rely on is wrong.
Verify the code book itself before trusting any training guides. I had to redo a whole bathroom vent because of a mistake in the printed guide. Now I make a point of checking for corrections online before starting any job. It saves the headache of arguing with inspectors over someone else's typo.