使用 minipage 命令在并排表格上添加标题

Question

我想知道为什么使用 \minipage 命令绘制两个不同的表格时无法看到两个表格标题：显然右侧表格标题与左侧表格标题重叠，但我不明白为什么。有人能帮帮我吗？提前谢谢。我留下了我写的 Latex 代码。

\documentclass[12pt, a4paper]{report}
\usepackage[margin=2.5cm]{geometry}
\renewcommand{\arraystretch}{1.5}
\usepackage{float}
\restylefloat{table}
\usepackage{caption}
\captionsetup{font=footnotesize,labelfont=bf}
\usepackage{array}
\usepackage{makecell}
\newcolumntype{x}[1]{>{\centering\arraybackslash\hspace{0pt}}p{#1}}
\newcolumntype{?}{!{\vrule width 1pt}}

\begin{document}
    
\begin{table}[H]
    \tiny
    \begin{minipage}[b]{0.4\textwidth}
        \centering
        \begin{tabular}{?x{26mm}?x{20mm}?}
            \Xhline{2.5\arrayrulewidth}
            \textbf{Ingredient} & \textbf{WT. Percent} \\ \Xhline{2.5\arrayrulewidth}
            R-45M (1\% A02246) & 13.83 \\ \hline
            IPDI & 0.86 \\ \hline
            HX-752 & 0.30 \\ \hline
            TPB & 0.01 \\ \hline
            \textit{Mg} & 22.00 \\ \hline
            AP & 62.80 \\ \hline
            \textit{Fe$_{\,2}$O$_{\,3}$} & 0.20 \\ \Xhline{2.5\arrayrulewidth}
        \end{tabular}
        \captionof{table}{\textit{Mg} composition}
        \label{tab: neutralized composition}
    \end{minipage}%
    \hspace{7mm}
    \begin{minipage}[b]{0.4\textwidth}
        \centering
        \begin{tabular}{?x{15mm}?x{35mm}?x{22mm}?}
            \Xhline{2.5\arrayrulewidth}
            \rule{0pt}{14pt}\shortstack{\textbf{Exhaust} \\ \textbf{Products}} & \shortstack{\textbf{Nozzle Exit} \\ (1000 psi - 14.7 psi - 1962 K)} & \shortstack{\textbf{50-50 Air} \\ (14.7 psi - 300 °F)} \\ \Xhline{2.5\arrayrulewidth}
            \textit{C$_{\,2}$H$_{\,4}$} & - & 0.128 \\ \hline
            \textit{CO} & 1.031 & - \\ \hline
            \textit{CO$_{\,2}$} & 0.035 & 0.406 \\ \hline
            \textit{HCl} & 0.417 & - \\ \hline
            \textit{MgCl$_{\,2}$} & 0.059 & 0.134 \\ \hline
            \textit{H$_{\,2}$} & 1.455 & - \\ \hline
            \textit{H$_{\,2}$O} & 0.218 & 0.686 \\ \hline
            \textit{MgO} & 0.845 & 0.318 \\ \Xhline{2.5\arrayrulewidth}
        \end{tabular}
        \captionof{table}{\textit{Mg} exhaust products}                    
        \label{tab: neutralized composition}
    \end{minipage}
\end{table}

\end{document}