Self-join example review in Books Online
Looks like you are right in all observations and it is a mistake.

They are two separate tables (not views) and a self-join means a table joined to itself (and even a view or derived table or CTE joined to itself). You might even consider a join between a table and a view derived from that table to be a self-join but it is not the case here either.

I suggest you submit a bug report.

Link: list of AdventureWorks tables.