subsequent-author-substitute-rule

I’m implementing the subsequent-author-substitute-rule and I’m having
problems in understanding the specification examples for "partial-first"
and “partial-each”.[1]

This is the description of “partial-each” substitution:

when one or more rendered names in the name variable match those in
the preceding bibliographic entry, the value of
subsequent-author-substitute substitutes for each matching name.
Matching starts with the first name, and continues up to the first
mismatch.

Why, in the example, the name “Doe” is not substituted in the third,
fifth and seventh references? Doesn’t it fit into the definition?

The same for “partial-first”: it seems to me that “Doe” should always be
substituted.

Can someone please explain to me the rules applied in the examples?

Best,
Andrea

[1] http://citationstyles.org/downloads/specification.html#reference-grouping

It looks to me like the example needs to be amended.

Frank