hyperref, makeidx and autonum combination leads to unexpected results

Question

This question is a follow-up of my other question:

1. If I use math equations with the autonum package and the hyperref package without setting the option hypertexnames to false then I receive those warnings:

   a. pdfTeX warning (ext4): destination with the same identifier (name{equation.X.X.X}) has been already used, duplicate ignored

   b. pdfTeX warning (ext4): destination with the same identifier (name{page.X}) has been already used, duplicate ignored

The second warning doesn't appear in my MWE below. I couldn't figure out which piece of my original code produce this warning, sorry for it. Note: The index linking works properly.

2. If I set the hyperref option hypertexnames to false than those warnings don't appear, but the index linking doesn't work properly (it links to the physical page one, which is the title page).

3. If I don't use the autonum package than the equation counting of the \[\] environment doesn't work at all and the equation linking (referencing) is particular wrong (in my MWE the equation P_F = F v gets the same link number as the equation P_N = \dot m w_N). Note: The index linking works properly, if I don't set the hypertexnames option to false, but than I have again above warnings.

I tried to cut as much as possible, but I don't know precise enough where the warnings appear, so my MWE is not really minimal, sorry for this. So if some one have the experience, to find out where the warnings come from, feel free to cut my MWE:

\documentclass[
               twoside,
               titlepage,
               abstract,
               ngerman
              ]{scrreprt}
\usepackage[T1]{fontenc}
\usepackage{
            lmodern,
            babel,
            makeidx,
            graphicx
           }
\usepackage{hyperref}
%\usepackage[hypertexnames=false]{hyperref}
%\usepackage{amsmath}
\usepackage{autonum}

\makeindex

\title{Title}
\author{Author}

\begin{document}

  \pagenumbering{Alph}
  \maketitle

  \begin{abstract}
    Abstract.
  \end{abstract}
  \cleardoublepage

  \renewcommand{\thepage}{\Roman{page}}
  \tableofcontents
  \cleardoublepage

  \pagenumbering{arabic}
  \chapter{Chapter}
    \section{Section one}
      Siehe Seite \pageref{Vortriebswirkungsgrad}\index{eta}.

    \section{Section two}
      \subsubsection{Vortriebswirkungsgrad}\label{Vortriebswirkungsgrad}
        \[\eta_p = \frac{P_F}{| P_N |}\label{eta_P}\]

      \subsubsection{Effizienzsteigerung eines Triebwerkes}\label{eta_g}
        \[\eta_g = \eta_t \eta_p\]

      \subsubsection{Schubleistung}
        \[P_F = F v\label{P_F}\]

      \subsubsection{Spezifische Nutzarbeit}
        \begin{align}
          w_N &= c_p \eta_t ( T_4 - T_3 )\label{w_N}\\
          P_N &= \dot m w_N.\label{P_N}
        \end{align}

      \subsubsection{Spezifischer Brennstoffverbrauch}
        \[B_s = \frac{\dot m_B}{F}.\]

      \subsubsection{Nebenstromverhältnis}\label{mu}
        \[\mu = \frac{\dot m_2}{\dot m_1}.\]

      \subsubsection{Maßnahmen für ZTL}
        \begin{align}
          P_F &= \eta_p | P_N |,
          \intertext{die Nutzleistung, aus Gleichung \eqref{P_N} auf Seite \pageref{P_N}, eingesetzt:}
              &= \eta_p | \dot m w_N |
          \intertext{und schließlich noch die spezifische Nutzarbeit, aus Gleichung \eqref{w_N} auf Seite \pageref{w_N}, ersetzt:}
              &= \eta_p | c_p\eta_t ( T_4 - T_3 ) |.
          \intertext{Außerdem gilt die Gleichung \eqref{P_F}, auf Seite \pageref{P_F}, nach wie vor:}
              &= F v.
        \end{align}

  \cleardoublepage
  \pagenumbering{Roman}
  \setcounter{page}{7}
  \printindex

\end{document}

What do I wrong and why is it so? Can I use all three packages without described issues?

Thank you for your help and effort in advance!