https://github.com/latex3/latex2e/issues/1781
To be dropped once debian's texlive gets it.
---
 docs/user_manual/user_manual.tex |   13 +++++++++++++
 1 file changed, 13 insertions(+)

--- a/docs/user_manual/user_manual.tex
+++ b/docs/user_manual/user_manual.tex
@@ -45,6 +45,19 @@
 \usepackage{a4}
 \usepackage{array}
 \usepackage{supertabular}
+
+\makeatletter
+\AddToHook{cmd/x@supertabular/after}
+   {%
+     \let\orig@startpbox@action\@startpbox@action
+     \let\@startpbox@action\@startpbox
+   }
+\AddToHook{cmd/ST@restore/after}
+   {%
+     \let\@startpbox@action\orig@startpbox@action
+   }
+\makeatother
+
 %\usepackage{pstricks}
 \usepackage{longtable}
 \usepackage{multirow}
