bug#23080: emacs-auctex: fill-paragraph always sets the modified flag

[Jaakov]

Dear maintainer:

Reproduce:

1) Create a tex file with some long multi-line text, e.g.,

% This buffer is for notes you don't want to save, and for
% Lisp evaluation.  If you want to create a file, visit that file with
% C-x C-f, then enter the text in that file's own buffer.

2) Open this file in Emacs.

3) Put the cursor into the text and press Alt-Q to adjust it to your 
column width. If there are less than two lines, add more text and press 
Alt-Q; repeat until you finally get at least two lines after Alt-Q.

4) a) Save the file.
   b) Observe that the buffer is indicated as stored.

5) a) Press Alt-Q again.
   b) Observe that the buffer contents did not change but the buffer is 
indicated as modified by the stars in the left lower corner.

This is contrary to the modified flag behavior as stated in
https://www.gnu.org/software/emacs/manual/html_node/elisp/Buffer-Modification.html

Some guy from suse claims that this bug is resolved upstream:
https://bugzilla.suse.com/show_bug.cgi?id=971814
Is it really the case?

Jaakov.