Odd/even page margins - an odd page has "even page margins"

Question

I'm having problem which drives me crazy.

I'm trying to make odd/even pages with different margins using option [twoside] according to this answer. Numbers in red are page numbers. The problem is, that my 9th page does not have larger left margin than the right one (as it should have as odd page and right page when opened book). I tried adding blank pages, using \cleardoublepage... Nothing helped me. My 9th page still behaves like even page - left margin lesser than the right one.

The code:

\documentclass[11pt,a4paper,twoside]{report}
\usepackage[top=2.5cm,bottom=2cm]{geometry}
\usepackage[cp1250]{inputenc}
\usepackage[czech]{babel}
\usepackage{hyperref}
\usepackage{xcolor}
\usepackage{nameref}
\hypersetup{
colorlinks,
linkcolor={red!50!black},
citecolor={blue!50!black},
urlcolor={blue!80!black}
}

% Czech single quotes
% left (\clq command)
\DeclareTextCommand{\clq}{T1}{\leavevmode\char13\nobreak\hskip0pt}
% right (\crq command)
\DeclareTextCommand{\crq}{T1}{{\edef\@SF{\spacefactor\the\spacefactor}%
\nobreak\char96\@SF\relax}}
% \juv{} command
\DeclareRobustCommand\juv[1]{{\leavevmode\clq#1\crq}}
%%

\newcommand{\blankpage}{
\newpage
\thispagestyle{empty}
\mbox{}
\newpage
}

\bibliographystyle{plain}
\usepackage{graphicx}
\usepackage{float}
\graphicspath{ {File path} }
\title{TITLE}

\usepackage{url}

\begin{document}
\pagenumbering{gobble}% Remove page numbers (and reset to 1)
\begin{titlepage}
\centering
{\huge\bfseries NAME\par}
\vspace*{8cm}
{\Huge\bfseries TITLE\dots\par}
\vspace*{13cm}
{\huge\bfseries YEAR\par}
\end{titlepage}

\pagenumbering{gobble}% Remove page numbers (and reset to 1)
\begin{titlepage}
\vspace*{8cm}
\noindent   
{\bfseries THANKS TO ...\par}
\vspace*{13cm}
\noindent
\end{titlepage}

\chapter*{PREFACE}
\addcontentsline{toc}{chapter}{PREFACE}
PREFACE TEXT
\newpage

\blankpage
% CONTENT
\tableofcontents

\pagenumbering{gobble}
\chapter*{\centering \vspace*{8cm} \textbf{FIRST PART}}
\setcounter{chapter}{1}
\addcontentsline{toc}{chapter}{FIRST PART}

\blankpage

\pagenumbering{arabic}% Arabic page numbers (and reset to 1)
\section*{SECTION 1}
\addcontentsline{toc}{section}{SECTION 1} % This section still behaves like "left-side page" even though is numbered as 9
TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT     TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT     TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT TEXT

So how to make the first section after chapter behave "like a proper odd page" having larger left margin than right margin?

Thank you

EDIT: Better explanation

Answer 1

Just in case anyone ever reads that question: This behaviour is caused by the fact, that the margins refer to the page counter. Everytime, the page numbering is changed, the page counter is reset.

i.e.

\pagenumbering{Roman}
%three pages full of text

\pagenumbering{arabic}
%plenty of other pages

The pagenumbering goes like

numbering:
A B C 1 2 3 4 ...
physical page:
1 2 3 4 5 6 7 ...

Now physical page 5 has page number 2. It should have oddsidemargin (because 5), but since the margin refers to the counter, evensidemargin is selected.

One workaround is to insert a blank page between roman pagenumbering and arabic pagenumbering (\newpage), another workaround is to invert oddsidemargin and evensidemargin:

\newdimen\tempdim
\tempdim=\oddsidemargin
\oddsidemargin=\evensidemargin
\evensidemargin=\tempdim

But the best solution is to use \cleardoublepage. This will print all floats (graphics and stuff) which are still in queue and might not have a suitable placement yet. If needed, the command inserts a page, so the next physical page is odd. Without this command, it might occur, that pictures appear in the wrong part (i.e. chapter) of the document.