[Help-bash] Backquote form of command substitution within double quotes

[Michael Convey]

The posix standard says the following:
====================================================
The backquote shall retain its special meaning introducing the other form
of command substitution (see Command Substitution
<http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_03>).
The portion of the quoted string from the initial backquote and the
characters up to the next backquote that is not preceded by a <backslash>,
having escape characters removed, defines that command whose output replaces
"`...`" when the word is expanded. Either of the following cases produces
undefined results:

   -

   A single-quoted or double-quoted string that begins, but does not end,
   within the "`...`" sequence
   -

   A "`...`" sequence that begins, but does not end, within the same
   double-quoted string

Source:
http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_02_03
====================================================

Is the first undefined case described by the following?
command "`command "argu`"ment"

Is the second undefined case described by the following?
command "`command" argument`

I'm not sure I understand these undefined cases (especially the 2nd one).
Thoughts?