\begin{proof} 和 \begin{problem} 在新部分不起作用

Question

我遇到了以下问题。因此，在我的文档中，我定义了新的定理环境问题，使用以下前导码

\theoremstyle{plain}
\newtheorem{eg}[theorem]{Example}

\theoremstyle{definition}
\newtheorem{remark}[theorem]{Remark}
\newtheorem{problem}[theorem]{Problem}

代码适用于前三部分。但是当我添加第四部分时，\begin{problem} 命令并没有给出下图所示的结果， 它给了我这个 同样的问题也发生在证明环境中。我想得到这个（通过使用命令 \begin{proof}[Euler's arcargument]） 但这就是我得到的 这里奇怪的是，这个问题只出现在第四部分，而不是前三部分。

这就是我的问题。如果有人能帮我解决这个问题，我将不胜感激。提前致谢。

PS. 以防万一，以下是我的完整序言

\documentclass[12pt]{article}
\usepackage{amsmath,amssymb,amsthm,amscd,graphicx,enumerate}
\usepackage{asymptote}

\usepackage{graphicx}
\usepackage[dvipsnames]{xcolor}
\usepackage{tikz,tkz-tab}
\usepackage{tkz-euclide}
\usetkzobj{all}

\usepackage{thmtools}
    \usepackage[framemethod=TikZ]{mdframed}

    \mdfdefinestyle{mdwhitebox}{%
        roundcorner = 10pt,
        linewidth=1pt,
        skipabove=12pt,
        innerbottommargin=9pt,
        skipbelow=2pt,
        linecolor=black,
        nobreak=true,
        backgroundcolor=White!5,
    }
    \declaretheoremstyle[
        headfont=\sffamily\bfseries\color{Black},
        mdframed={style=mdwhitebox},
        headpunct={\\[3pt]},
        postheadspace={0pt}
    ]{lembox}

    \mdfdefinestyle{mdrecbox}{%
        linewidth=0.5pt,
        skipabove=12pt,
        frametitleaboveskip=5pt,
        frametitlebelowskip=0pt,
        skipbelow=2pt,
        frametitlefont=\bfseries,
        innertopmargin=4pt,
        innerbottommargin=8pt,
        nobreak=true,
        backgroundcolor=White!5,
    }
    \declaretheoremstyle[
        headfont=\bfseries\color{Black},
        mdframed={style=mdrecbox},
        headpunct={\\[3pt]},
        postheadspace={0pt},
    ]{defbox}

    \mdfdefinestyle{mdbluebox}{%
        roundcorner = 10pt,
        linewidth=1pt,
        skipabove=12pt,
        innerbottommargin=9pt,
        skipbelow=2pt,
        linecolor=blue,
        nobreak=true,
        backgroundcolor=TealBlue!5,
    }
    \declaretheoremstyle[
        headfont=\sffamily\bfseries\color{MidnightBlue},
        mdframed={style=mdbluebox},
        headpunct={\\[3pt]},
        postheadspace={0pt}
    ]{thmbluebox}


\declaretheorem[style=thmbluebox,name=Theorem,numberwithin=section]{theorem}
\declaretheorem[style=defbox,name=Definition,numberwithin=section]{defn}
\declaretheorem[style=lembox,name=Lemma,sibling=theorem]{lemma}

\newenvironment{soln}{\begin{proof}[Solution]}{\end{proof}}

\theoremstyle{plain}
\newtheorem{eg}[theorem]{Example}

\theoremstyle{definition}
\newtheorem{remark}[theorem]{Remark}
\newtheorem{problem}[theorem]{Problem}


\numberwithin{equation}{section}

\oddsidemargin 0in
\textwidth 6.5in
\textheight 9in
\topmargin 0in
\headheight 0in
\headsep 0in

%link refrence set up
\usepackage{xcolor}
\usepackage[colorlinks=true]{hyperref}   
\hypersetup{urlcolor=RubineRed,linkcolor=RoyalBlue,citecolor=ForestGreen}
\usepackage[nameinlink]{cleveref}

\newcommand{\vocab}[1]{\textbf{\color{blue} #1}}

编辑1：这是人们要求的 MWE。

\documentclass[12pt]{article}
\usepackage{amsmath,amssymb,amsthm,amscd,graphicx,enumerate}
\usepackage{asymptote}

\usepackage{graphicx}
\usepackage[dvipsnames]{xcolor}
\usepackage{tikz,tkz-tab}
\usepackage{tkz-euclide}
\usetkzobj{all}

\usepackage{thmtools}
    \usepackage[framemethod=TikZ]{mdframed}

    \mdfdefinestyle{mdwhitebox}{%
        roundcorner = 10pt,
        linewidth=1pt,
        skipabove=12pt,
        innerbottommargin=9pt,
        skipbelow=2pt,
        linecolor=black,
        nobreak=true,
        backgroundcolor=White!5,
    }
    \declaretheoremstyle[
        headfont=\sffamily\bfseries\color{Black},
        mdframed={style=mdwhitebox},
        headpunct={\\[3pt]},
        postheadspace={0pt}
    ]{lembox}

    \mdfdefinestyle{mdrecbox}{%
        linewidth=0.5pt,
        skipabove=12pt,
        frametitleaboveskip=5pt,
        frametitlebelowskip=0pt,
        skipbelow=2pt,
        frametitlefont=\bfseries,
        innertopmargin=4pt,
        innerbottommargin=8pt,
        nobreak=true,
        backgroundcolor=White!5,
    }
    \declaretheoremstyle[
        headfont=\bfseries\color{Black},
        mdframed={style=mdrecbox},
        headpunct={\\[3pt]},
        postheadspace={0pt},
    ]{defbox}

    \mdfdefinestyle{mdbluebox}{%
        roundcorner = 10pt,
        linewidth=1pt,
        skipabove=12pt,
        innerbottommargin=9pt,
        skipbelow=2pt,
        linecolor=blue,
        nobreak=true,
        backgroundcolor=TealBlue!5,
    }
    \declaretheoremstyle[
        headfont=\sffamily\bfseries\color{MidnightBlue},
        mdframed={style=mdbluebox},
        headpunct={\\[3pt]},
        postheadspace={0pt}
    ]{thmbluebox}

\declaretheorem[style=thmbluebox,name=Theorem,numberwithin=section]{theorem}
\declaretheorem[style=defbox,name=Definition,numberwithin=section]{defn}
\declaretheorem[style=lembox,name=Lemma,sibling=theorem]{lemma}

\newenvironment{soln}{\begin{proof}[Solution]}{\end{proof}}

\theoremstyle{plain}
\newtheorem{eg}[theorem]{Example}

\theoremstyle{definition}
\newtheorem{remark}[theorem]{Remark}
\newtheorem{problem}[theorem]{Problem}


\numberwithin{equation}{section}

\oddsidemargin 0in
\textwidth 6.5in
\textheight 9in
\topmargin 0in
\headheight 0in
\headsep 0in

%link refrence set up
\usepackage{xcolor}
\usepackage[colorlinks=true]{hyperref}          
\hypersetup{urlcolor=RubineRed,linkcolor=RoyalBlue,citecolor=ForestGreen}
\usepackage[nameinlink]{cleveref}

\newcommand{\vocab}[1]{\textbf{\color{blue} #1}}


\begin{document}
\title{Notes}
\author{}
\date{}
\maketitle

\tableofcontents
\eject

\section{Section 1}

\begin{problem}
Works fine here
\end{problem}

\newpage

\section{Section 2}

\begin{problem}
Works fine here
\end{problem}

\newpage

\section{Section 3}

\begin{problem}
Works fine here
\end{problem}

\begin{remark}
A tikz diagram
\begin{center}
\begin{tikzpicture}
\tkzInit[xmin=-0.8,ymin=-1.3,xmax=5.2,ymax=1.3]
\tkzAxeX[
   label=\hspace{4mm}{$x$},
   very thick, % increase width of axes lines
   label options={font=\Large}, % increase font size 
   orig=false % don't print zeros
]

\tkzAxeY[
   label=\raisebox{4mm}{$y$},
   very thick, % increase width of axes lines
   label options={font=\Large,}, % increase font size 
   orig=false % don't print zeros
]

\draw (0,1)--(2,1)--(2.5,-1)--(3,1)--(10/3,-1)--(11/3,1)--(4,1)--(17/4,-1)-- 
 (18/4,1)--(19/4,-1)--(5,1);
\end{tikzpicture}
\end{center}
Something happen after this tikz diagram
\end{remark}

\section{Test}

\begin{problem}
 Fails here
\end{problem}

\end{document}