Change abstract title in IEEEtran when used with other language

Question

When I use the ieeetran-class with a german babel-package loaded, the title of the abstract automatically gets translated to Zusammenfassung. However I'd like it to be Kurzfassung.

The solution one can find all over the web, is just to use:

\def\abstractname{Kurzfassung}

Why is that approach not working in my case?

I use lualatex, here is my minimal example:

\documentclass{IEEEtran}

\usepackage[T1]{fontenc}
\usepackage[utf8]{luainputenc}
\usepackage[ngerman]{babel}

\def\abstractname{Kurzfassung}
\def\IEEEkeywordsname{Stichwörter}

\usepackage{blindtext}

\begin{document}

\begin{abstract}
\blindtext
\end{abstract}

\begin{IEEEkeywords} 
    myKeyword
\end{IEEEkeywords}

\section{Einleitung}
\blindtext

\end{document}

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But the appearance of the abstract remains unchanged in the german default Zusammenfassung: