How to Inspect the Exterior Course - Decks

I /think/ I found a typo in the course material. I only found it by chance. The Exterior Course material says

The footing near the home may not be placed on undisturbed soil. Some codes
consider soil to be undisturbed if it hasn’t been disturbed in more than five years.

Page 262

When I download the How to Inspect Decks document, it says

The footing near the home should not be placed in disturbed soil. Disturbed soils are
those which have been altered as a result of grading or construction, etc., giving the soil
variable characteristics.

Page 10

From what I’m reading online, it appears the “Decks” course is wrong.

Thoughts?

Also, 2018 IRC says undisturbed…

https://codes.iccsafe.org/content/IRC2018/chapter-4-foundations

Report it to the Education Department.