Inconsistent spacing in itemize environment inside tikz node inside center environment

Question

I have noticed inconsistent spacing when using itemized lists in a TikZ node when the tikzpicture is inside a centering environment.

I have the following code:

\documentclass{memoir}
\usepackage{tikz}
\begin{document}
    \begin{center}
        \begin{tikzpicture}
            \node[align=left, text width=5cm] (0,0)
            {
                \textbf{Heading 1}
                \begin{itemize}
                    \item{item 1}
                \end{itemize}
            };
            \node[align=left, text width=5cm] at (0,2)
            {
                \textbf{Heading 2}
                \begin{itemize}
                    \item{item 2}
                \end{itemize}
            };
        \end{tikzpicture}
    \end{center}
\end{document}

and I get a result like this:

However, when I have the nodes in different order like this:

\documentclass{memoir}
\usepackage{tikz}
\begin{document}
    \begin{center}
        \begin{tikzpicture}
            \node[align=left, text width=5cm] at (0,2)
            {
                \textbf{Heading 2}
                \begin{itemize}
                    \item{item 2}
                \end{itemize}
            };
            \node[align=left, text width=5cm] (0,0)
            {
                \textbf{Heading 1}
                \begin{itemize}
                    \item{item 1}
                \end{itemize}
            };
        \end{tikzpicture}
    \end{center}
\end{document}

I get this output:

If I remove the centering environment around the tikzpicture, then both lists are rendered with similar spacing like this:

Why is this happening? Is this a bug? Is there a way that I can fix this?

I'm using TeX Live 2023 on Linux.