I am experiencing bad behaviors with \ref and \eqref in amsart and article class (as far as I know).
For example, I see this:

Environment

• TeXstudio: 4.8.4
• Qt: 6.7.2
• OS: Windows 11
• TeX distribution: texlive

Expected behavior

I should not see any label missing sign on existing labeled equations.

Actual behavior

How to reproduce

\documentclass[11pt]{amsart}
\usepackage[english]{babel}
\usepackage[latin1]{inputenc}
\usepackage{amssymb,geometry,color,xcolor,graphicx}
\usepackage{amsmath,amsthm}
\usepackage{booktabs}
\usepackage{caption}
\usepackage{datetime}
\usepackage{dsfont}
\usepackage{amstext}
\usepackage{graphicx}
\usepackage{fancyhdr}
\usepackage{latexsym}
\usepackage{mathrsfs}
%\usepackage{stmaryrd}
\usepackage{cases}
\usepackage{mathtools}
\usepackage{bm}
\usepackage{subfigure}
\usepackage{hyperref}
\hypersetup{
colorlinks=true, %set true if you want colored links
linktoc=all, %set to all if you want both sections and subsections linked
linkcolor=blue, %choose some color if you want links to stand out
}
\geometry{tmargin=3cm,bmargin=4cm,lmargin=3.5cm,rmargin=3.5cm}
\hyphenation{}

\newcommand{\de}{\mathrm{d}}

\begin{document}

\begin{equation}\label{eq:stocKdV}
\begin{cases}
\de u(x,t)=(6u(x,t)u_x(x,t)-u_{xxx}(x,t))\de t+\varepsilon u(x,t)\de W(t), & x\in(-\infty,\infty),;t\in(0,T), \
u(x,0)=-2k^2\sech^2(kx),
\end{cases}
\end{equation}
\ref{eq:stocKdV}
\eqref{eq:stocKdV}

\end{document}