Grafik überlappt Text trotz Platz (textfraction, geometry, parskip)

% Document class
\documentclass[ a5paper, % type of paper
				fontsize=9pt, 
				parskip=half, % distance between paragraphs shall be half a line
				usegeometry, % facilitates use of geometry package into scrbook class
				]{scrbook}
\usepackage[english, ngerman]{babel}
 
\usepackage{geometry}
\newgeometry{left=5cm, right=1.6cm, top=1.1cm, bottom=1.1cm, % margins from page to body
	includeheadfoot, % header and footer are considered as part of the body, hence are placed within margins
	headsep=0.6cm, % vertical distance from top of textbody to bottom of header
	footskip=0.9cm, % vertical distance from bottom of textbody to top(?) of footer
	footnotesep=0.9cm, % vertical distance from bottom of textbody to top(?) of footnotes
}
\usepackage{showframe}
 
\renewcommand{\textfraction}{0.1}	% allow minimal text w. figs
\usepackage[draft]{pgf}
 
 
\begin{document}
 
and classified correctly. Then, the linear fit described in step three can be correctly performed (see right hand side of Fig.~\ref{fig:06_FSM_preoptim}).
 
\begin{figure} [htbp]
	\centering
	\begin{pgfpicture}
		\pgftext{\pgfimage[width=\textwidth,height=12.927cm]{dummy}}
	\end{pgfpicture}
	\caption{Diagram, in which the benefits of the preoptimization before the linear fit are demonstrated}
	\label{fig:06_FSM_preoptim}
\end{figure}
 
\section{Next section}
 
In contrast to ...
 
\end{document}