When can "because" introduce a non-restrictive clause?

Even if rare, when can this happen? Any trustworthy examples?

11. Do Not Use a Comma Before “Because”

Do not use a comma before “because” unless “because” introduces a nonrestrictive clause. That rarely happens.

Incorrect: This is contradictory to the common practice, because, according to that practice, the title

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of ownership will not be transferred to the buyer until payment is completed.

Correct: This is contradictory to the common practice because, according to that practice, the title of ownership will not be transferred to the buyer until payment is completed.

Bahrych, Merino. Legal Writing and Analysis in a Nutshell 5th edition (2017). p. 226-7.