Error producing latex tables related to standalone non-preview

[ropeladder]

Describe the bug
We are running into a compile error on latex tables generated with the non-preview standalone document class. (which appears to have been introduced in this commit, line 235: 0da5c69)

I suppose technically it's a problem with latex or the standalone document type. I'm seeing it using:

• pdfTeX 3.14159265-2.6-1.40.21 (TeX Live 2020)
• pdfTeX 3.14159265-2.6-1.40.19 (TeX Live 2018)
• XeTeX 3.14159265-2.6-0.99999 (TeX Live 2018)

...running on an elderly Ubuntu machine. Obviously this could be a problem due our old versions of things.

To Reproduce
Minimal tex example: (This is a minimal example; in reality our table has actual content.)

\documentclass[border=1mm]{standalone}
\usepackage{threeparttable}
\begin{document}
\begin{table}
\begin{threeparttable}
\end{threeparttable}
\end{table}
\end{document}

Produces:

! LaTeX Error: Something's wrong--perhaps a missing \item.

Setting \documentclass[border=1mm, preview]{standalone} runs fine. Alternatively, if we don't use kable_style() then the additional \begin{table} line is not included, and that also runs fine.