exam: two-column questions

Both itemsep and parskip take on different values in the three examples, with the change occurring in begin{subparts}. This does not occur when using a parbox instead. Nor can I find the code responsible for the change.

I included the following to try to equalize both the horizontal and vertical spacing for the three solutions.

documentclass{exam}
usepackage[a4paper, top=1.9cm, left=2cm, right=2cm, bottom=2.2cm,showframe]{geometry}
usepackage{mathtools,paracol}
usepackage{graphbox}
usepackage{caption}

columnsep=0.01textwidth

begin{document}
    begin{questions}
        setlength{rightpointsmargin}{2.5cm}
        pointsdroppedatright
        marginpointname{%}
        bigskip
        question
        begin{parts}
            part
            setlength{tabcolsep}{0mm}
            begin{tabular}[t]{@{}p{0.65linewidth}@{hspace{columnsep}}p{0.34linewidth}@{}}
                Figure ref{test1} shows a pyramid $ABCD-E$. Suppose that $AE=13$, $AC=10$. Find the followings:theparskip
                begin{subparts}
                    subpart[1] Height $ME$.theparskipdroppoints
                    subpart[2] Area of base square $ABCD$.droppoints
                    subpart[2] Volume of pyramid $ABCD-E$.droppoints
                end{subparts} & includegraphics[width=linewidth,align=t]{example-image-a}
                captionof{figure}{tabular approach}label{test1}
            end{tabular}
        end{parts}
        %
        question
        begin{parts}
            part
            parbox[t]{0.65linewidth}{%
                Figure ref{test3} shows a pyramid $ABCD-E$. Suppose that $AE=13$, $AC=10$. Find the followings:
                %par parskip=theparskippar itemsep=theitemsep
                begin{subparts}%rlap{parskip=theparskip{ }itemsep=theitemsep}
                    subpart[1] Height $ME$.droppoints
                    subpart[2] Area of base square $ABCD$.droppoints
                    subpart[2] Volume of pyramid $ABCD-E$.droppoints
                end{subparts}
            }hfill
            begin{minipage}[t]{0.34linewidth}
                includegraphics[width=linewidth,align=t]{example-image-b}
                captionof{figure}{minipage approach}label{test3}
            end{minipage}
        end{parts}
        %
        question
        
        begin{parts}
            part
            setcolumnwidth{dimexpr textwidth-columnsep-0.34linewidth}
            begin{paracol}{2} 
                Figure ref{test2} shows a pyramid $ABCD-E$. Suppose that $AE=13$, $AC=10$. Find the followings:theparskip
                begin{subparts}
                    subpart[1] Height $ME$.droppoints
                    subpart[2] Area of base square $ABCD$.droppoints
                    subpart[2] Volume of pyramid $ABCD-E$.droppoints
                end{subparts}
                switchcolumn
                begin{figure}[ht]
                    includegraphics[width=linewidth]{example-image-c}
                    caption{paracol approach}label{test2}
                end{figure}
            end{paracol}
        end{parts}
    end{questions}
end{document}