Issue
As discovered in PR #2107 in the comment here, the labels and captions of environments within another environment are incorrectly displayed in the top-level fold, even if the top-level fold has its own labels and captions.

Observed Behaviour

\begin{thm}[Theorem 1]
\label{thm:theorem_1}
\caption{theorem 1 caption}
...
\begin{figure}
\label{fig:figure_1}
...
\caption{figure 1 caption}
\end{figure}
...
\end{thm}

is currently folded as:

\begin{thm}[Theorem 1]     figure 1 caption                                             (fig:figure_1)

Expected Behaviour

instead of the proper folding:

\begin{thm}[Theorem 1]     theorem 1 caption                                         (thm:theorem_1)

This is caused by the fold_parse_label and fold_parse_caption functions here:

Fixing this will involve rewriting the function to not search subfolds.

Output from VimtexInfo

Should be irrelevant in this case, but for the sake of consistency:

System info
  OS: Manjaro Linux
  Vim version: VIM 8.2 (1-3171)
  Has clientserver: true
  Servername: undefined (vim started without --servername)