I have noticed some odd extra vertical when placing boxes in a twocolumn layout:
\documentclass[a5paper]{article}
\usepackage{calc}
% issue only happens with adjustbox loaded
\usepackage{adjustbox}
\parindent=0pt
\fboxrule=1pt
\fboxsep=5mm
\begin{document}
\twocolumn
\fbox{\begin{minipage}{\linewidth-2\fboxrule-2\fboxsep}
\section*{sec1}
test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test
\end{minipage}}
\vfill
\fbox{\begin{minipage}{\linewidth-2\fboxrule-2\fboxsep}
\section*{sec2}
test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test
\end{minipage}}
\vfill
\fbox{\begin{minipage}{\linewidth-2\fboxrule-2\fboxsep}
\section*{sec3}
test test test test test test test test test test test test test test test test test test test test test test
\end{minipage}}
\vfill
\fbox{\begin{minipage}{\linewidth-2\fboxrule-2\fboxsep}
\section*{sec4}
test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test
\end{minipage}}
\end{document}
Here are the outputs for lualatex
and pdflatex/xelatex
As you can see, the lualatex version has some extra space at the bottom of the right column (it seems to be around 5pt). As the comment says, this only occurs with the adjustbox package loaded.
Is this a bug (and if so, where) and can I work around it?
Using LuaTeX v1.0.4/TeX Live 2017.

