# Different results of \mag statement

The following example gives different results for pdfLaTeX and LuaLaTeX. I use a recent TeX Live 2019 installation.

\documentclass[a4paper]{article}
\usepackage{geometry}
\mag=250 %
\setlength\parindent{0pt}
\begin{document}
\Huge
\LaTeX \hfill \LaTeX
\vfill
\LaTeX \hfill \LaTeX
\end{document}

1. pdfLaTeX: A page on A8 paper (53mm x 74mm)

2. LuaLaTeX: A page on A4 paper (210mm x 297mm)

I use the package »geometry« only for transfering the page size informations to the output file. Without »geometry« I get the same results. Why ist the size not changed with LuaLaTeX? Can anyone enlighten me? Thanks in advance.