使用 `\useshortskip` 时 `cases` 的间距太短

Question

这是 Overleaf MWE。

示例代码：

\documentclass{book}

\usepackage{indentfirst}

\usepackage{nccmath}    % align & gather doesn't use shortskip: https://tex.stackexchange.com/a/386266/206774
\useshortskip           % nccmath seems to fix that even without this line


\begin{document}

1st case case case case case case case case 

\[\begin{cases}
    D: \text{wheel diameter} \\
    A = l \sin{\beta_1} \\
\end{cases}\]

2nd case case case case case case case case 

\[\begin{cases}
    D: \text{wheel diameter} \\
    A = l \sin{\beta_1} \\
\end{cases}\]

\end{document}

这就是问题：

看来只有第一个cases受到影响。