svg不会显示包含g标签的文本

我把我的问题简化为一个最小的工作示例。此代码段不会显示任何文本:

<?xml version="1.0" encoding="iso-8859-1" standalone="no"?> 
<svg viewBox="-361.65944 -228.02199 723.31888 284.92749 ">
    <text > 
        <g fill="#000">
            <g stroke="none">
                <tspan font-family="cmr" font-size="17">Render</tspan>
                <tspan font-family="cmr" font-size="17">Process</tspan>
            </g>
        </g>
    </text> 
</svg>

现在,如果我评论一下这两个 g 标签,显示文本:

<?xml version="1.0" encoding="iso-8859-1" standalone="no"?> 
<svg viewBox="-361.65944 -228.02199 723.31888 284.92749 ">
    <text > 
        <!-- <g fill="#000"> -->
            <!-- <g stroke="none"> -->
                <tspan font-family="cmr" font-size="17">Render</tspan>
                <tspan font-family="cmr" font-size="17">Process</tspan>
            <!-- </g> -->
        <!-- </g> -->
    </text> 
</svg>

为什么会这样?我通过以下方式生成svg htlatex 出自以下tikz文件:

\documentclass[tikz]{standalone}
\def\pgfsysdriver{pgfsys-tex4ht.def} 

\usepackage{tikz}
\usepackage{anyfontsize}
\usetikzlibrary{shapes, positioning}
\begin{document}
\begin{tikzpicture}[
    main/.style={rounded corners, fill=blue!15, align=center, inner sep=10, text width=6cm, minimum height=4cm, font={\fontsize{50 pt}{40 pt}\selectfont}},
    render/.style={rounded corners, fill=red!15, align=center, inner sep=6, text width=5cm, minimum height=3.5cm, font={\fontsize{40 pt}{40 pt}\selectfont}},
]
    \node[main] (main) {Main Process};
    \node[render] [below=of main, xshift=10cm, yshift=-1.5cm] (render1) {Render Process};
    \node[render] [below=of main, xshift=3.2cm, yshift=-1.5cm] (render2) {Render Process};
    \node[render] [below=of main, xshift=-3.2cm, yshift=-1.5cm] (render3) {...};
    \node[render] [below=of main, xshift=-10cm, yshift=-1.5cm] (render4) {Render Process};

    \draw [->] (main) -- (render1.north);
    \draw [->] (main) -- (render2.north);
    \draw [->] (main) -- (render3.north);
    \draw [->] (main) -- (render4.north);
\end{tikzpicture}
\end{document}

我完全不知道这里发生了什么。我真的很感激任何形式的投入!