Disable vertical spacing in Clean Thesis

Question

When I use the article class in latex and I have a definition, followed by a huge align environment, latex produces the following output

I am using the thesis template http://cleanthesis.der-ric.de/ with a paragraph ( as explained in Getting back the paragraph in cleanThesis?).

Here, the definition becomes spread over the whole page like this

How can I prevent that from happening and get the result like in a article latex document?

Here is the code for the first example in the article class:

\documentclass{article}

\usepackage{amsthm}
\usepackage{float}



\theoremstyle{plain}
\newtheorem{theorem}{Theorem}
\newtheorem{lemma}[theorem]{Lemma}
\newtheorem{prop}[theorem]{Proposition}
\newtheorem{corollary}[theorem]{Corollary}

\theoremstyle{definition}
\newtheorem{definition}[theorem]{Definition}

\usepackage{dsfont}

\usepackage{mdframed}
\usepackage{framed}
\usepackage{lipsum}

\usepackage{amsfonts}
\usepackage{amsmath}


\newcommand{\normstandard}[1]{\left\lVert#1\right\rVert}

\begin{document}
Some Text
    \begin{definition}
    Any linear operator $P \colon L^1(\mu) \to L^1(\mu)$ satisfying
    \begin{itemize}
    \item[$(i)$] $Pf \geq 0 \quad \text{and}$
    \item[$(ii)$] $\int_E (Pf)(x) \,\mu(dx) = \int_E f(x) \, \mu(dx)$
    \end{itemize}
    \end{definition}

     a little text
    \begin{align*}
    \nu_A \left(\bigcup_{k\in \mathbb{N}} A_k \right) &=  \lim_{n \to \infty} 
        \int_A \left( P \mathds{1}_{D_n} \right)(x) \, \mu(dx) \\
        &= \lim_{n \to \infty} 
        \int_A \left( P \left(\sum_{k\in \mathbb{N}} \mathds{1}_{D^k_n} \right) \right)(x) \, \mu(dx) \\
        &\overset{(*)}{=}\lim_{n \to \infty} 
        \int_A \sum_{k\in \mathbb{N}}\left( P  \mathds{1}_{D^k_n} \right)(x) \, \mu(dx) \\
        &\overset{(**)}{=}\lim_{n \to \infty} 
        \sum_{k\in \mathbb{N}}\int_A \left( P  \mathds{1}_{D^k_n} \right)(x) \, \mu(dx) \\
        &\overset{(**)}{=}\sum_{k\in \mathbb{N}}\lim_{n \to \infty} 
        \int_A \left( P  \mathds{1}_{D^k_n} \right)(x) \, \mu(dx) \\
        &\overset{(**)}{=} 
        \sum_{k\in \mathbb{N}}\int_A \lim_{n \to \infty} \left( P  \mathds{1}_{D^k_n} \right)(x) \, \mu(dx), \\
        &= \lim_{n \to \infty} 
        \int_A \left( P \left(\sum_{k\in \mathbb{N}} \mathds{1}_{D^k_n} \right) \right)(x) \, \mu(dx) \\
        &\overset{(*)}{=}\lim_{n \to \infty} 
        \int_A \sum_{k\in \mathbb{N}}\left( P  \mathds{1}_{D^k_n} \right)(x) \, \mu(dx) \\
        &\overset{(**)}{=}\lim_{n \to \infty} 
        \sum_{k\in \mathbb{N}}\int_A \left( P  \mathds{1}_{D^k_n} \right)(x) \, \mu(dx) \\
        &\overset{(**)}{=}\sum_{k\in \mathbb{N}}\lim_{n \to \infty} 
        \int_A \left( P  \mathds{1}_{D^k_n} \right)(x) \, \mu(dx) \\
        &\overset{(**)}{=} 
        \sum_{k\in \mathbb{N}}\int_A \lim_{n \to \infty} \left( P  \mathds{1}_{D^k_n} \right)(x) \, \mu(dx), \\
        &= \lim_{n \to \infty} 
        \int_A \left( P \left(\sum_{k\in \mathbb{N}} \mathds{1}_{D^k_n} \right) \right)(x) \, \mu(dx) \\
        &\overset{(*)}{=}\lim_{n \to \infty} 
        \int_A \sum_{k\in \mathbb{N}}\left( P  \mathds{1}_{D^k_n} \right)(x) \, \mu(dx) \\
        &\overset{(**)}{=}\lim_{n \to \infty} 
        \sum_{k\in \mathbb{N}}\int_A \left( P  \mathds{1}_{D^k_n} \right)(x) \, \mu(dx) \\
        &\overset{(**)}{=}\sum_{k\in \mathbb{N}}\lim_{n \to \infty} 
        \int_A \left( P  \mathds{1}_{D^k_n} \right)(x) \, \mu(dx) \\
        &\overset{(**)}{=} 
        \sum_{k\in \mathbb{N}}\int_A \lim_{n \to \infty} \left( P  \mathds{1}_{D^k_n} \right)(x) \, \mu(dx), \\
        &{=} 
        \sum_{k\in \mathbb{N}} \nu_A( A_k )
    \end{align*}        
    where we have used in $(*)$ the continuity of $P$, in particular
    \begin{align*}
        \int_A \left| \left( P \left(\sum_{k\in \mathbb{N}} \mathds{1}_{D^k_n} \right) \right)(x)- \sum_{k=1}^m \left( P  \mathds{1}_{D^k_n} \right)(x) \right| \, \mu(dx)
        \leq \normstandard{P} \normstandard{\sum_{k=m+1}^\infty \mathds{1}_{D^k_n} } \to 0
    \end{align*}
    some information
\end{document}