Chemfig curved arrows in the wrong place [solved]

Question

EDIT: I now know what causes the problem. I failed to mention in this post that I used a header file and the command \include. I thought it would make no difference, and I was wrong. \input, however, works as expected.

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I'm trying to put curvedarrows in my chemfig diagrams but the curved arrows are placed beside the whole scheme instead of on top.

Screenshot of my unfinished reaction scheme:

You can see the curved arrow to the right of the imine molecule, even though I've placed the nodes on the aldehyde.

I tried to draw the aldehyde on its own with the curved arrow too, but it failed just the same.

And the relevant code:

\documentclass[a4paper]{article}
\usepackage{chemfig}
\usepackage{mhchem}
\begin{document}
\setchemfig{atom sep=2em}
\begin{figure}[h]
    \centering
    \scriptsize
    \sffamily
    \mhchemoptions{font=sf}
    \schemestart
    \chemfig{(-[:-150]R)(=[@{db}:90]@{o}O)-[:-30]H}
    +
    \chemfig{N(-[:-150]H)(-[:90]H)-[:-30]R}
    \arrow(s1--int){<=>[\ce{H+}]}
    \chemname{\chemfig{(-[:-150]R)(-[:120]HO)(-[:60]N(-[:120]H)-[:0]R)-[:-30]H}}{hemiaminal}
    +
    \arrow{<=>[\ce{H+}]}
    \chemname{\chemfig{(-[:-150]R)(=[:90]N-[:30]R)-[:-30]H}}{imine}
    \arrow(@s1--s2){<=>[\ce{H+}]}[-90]
    \schemestop
    \chemmove{\draw(db)..controls +(-30:4mm) and +(0:4mm)..(o);}
\end{figure}
\end{document}

\documentclass[a4paper]{article}

\usepackage{chemfig}
\usepackage{mhchem}

\begin{document}

\setchemfig{atom sep=2em}

\begin{figure}[h]
    \centering
    \scriptsize
    \sffamily
    \mhchemoptions{font=sf}
    \schemestart
    \chemfig{(-[:-150]R)(=[@{db}:90]@{o}O)-[:-30]H}
    \schemestop
    \chemmove{\draw(db)..controls +(-30:4mm) and +(0:4mm)..(o);}
\end{figure}

\end{document}

The chemfig manual mentions something about the viewer supporting "picture remembering", but I have no idea what this means.

Thanks for any and all help.

Edited to make the code compilable