asciidoc: wrong unindented warning in nested lists

[Jibec]

when converting this asciidoc content to pot:

. Install Spotify:
.. Using Gnome Software:
... Head to the link:https://flathub.org/apps/details/com.spotify.Client[Spotify page on Flathub].
... Click "install", and choose to open the file using Gnome Software.
... Click "install" in Gnome Software.
... Click "launch" to run Spotify once installed.

I get this warning:

./index.adoc:3: It seems that you are adding unindented content to an item.
The standard allows this, but you may still want to change your document
to use indented text to provide better visual clues to writers.
./index.adoc:4: It seems that you are adding unindented content to an item.
The standard allows this, but you may still want to change your document
to use indented text to provide better visual clues to writers.
./index.adoc:5: It seems that you are adding unindented content to an item.
The standard allows this, but you may still want to change your document
to use indented text to provide better visual clues to writers.
./index.adoc:6: It seems that you are adding unindented content to an item.
The standard allows this, but you may still want to change your document
to use indented text to provide better visual clues to writers

I get this pot:

# SOME DESCRIPTIVE TITLE
# Copyright (C) YEAR Free Software Foundation, Inc.
# This file is distributed under the same license as the PACKAGE package.
# FIRST AUTHOR <EMAIL@ADDRESS>, YEAR.
#
#, fuzzy
msgid ""
msgstr ""
"Project-Id-Version: PACKAGE VERSION\n"
"POT-Creation-Date: 2020-04-18 23:08+0200\n"
"PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
"Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
"Language-Team: LANGUAGE <LL@li.org>\n"
"Language: \n"
"MIME-Version: 1.0\n"
"Content-Type: text/plain; charset=CHARSET\n"
"Content-Transfer-Encoding: 8bit\n"

#. type: Plain text
#: ./index.adoc:2
msgid "Install Spotify:"
msgstr ""

#. type: Plain text
#: ./index.adoc:6
msgid ""
"Using Gnome Software: ... Head to the "
"link:https://flathub.org/apps/details/com.spotify.Client[Spotify page on "
"Flathub].  ... Click \"install\", and choose to open the file using Gnome "
"Software.  ... Click \"install\" in Gnome Software.  ... Click \"launch\" to "
"run Spotify once installed."
msgstr ""

and the generated adoc is:

. Install Spotify:
.. Using Gnome Software: ... Head to the
   link:https://flathub.org/apps/details/com.spotify.Client[Spotify page on
   Flathub].  ... Click "install", and choose to open the file using Gnome
   Software.  ... Click "install" in Gnome Software.  ... Click "launch" to run
   Spotify once installed.

The specification says it can go up to 5 levels: https://asciidoctor.org/docs/asciidoc-syntax-quick-reference/#lists

thanks for your help
kind ping to @bexelbie