# Weird chemfig 1.33 behaviour with polymerdelim

I observed a very weird behaviour regarding chemfig and the polymer delimiters. I have created a minimal working example:

main.tex:

\documentclass[12pt,a4paper,ngerman]{article}
\include{preamble}
%\usepackage[utf8]{inputenc}
%\usepackage{chemfig}
\begin{document}
\chemfig{\vphantom{CH_2}-[@{op,.75}]CH_2-CH_2-[@{cl,0.25}]}
\polymerdelim[height = 5pt, indice = \!\!n]{op}{cl}
\end{document}


preamble.tex:

\usepackage[utf8]{inputenc}
\usepackage{chemfig}


I get the following output from this:

As you can see, the brackets are next to the formula whereas they should be around the formula. When I comment the include statement in main.tex and instead uncomment the two lines below, everything works like it should.

How is this possible? I want to have the preamble in a separate document though, because it is much longer in my real document.

• Welcome to TeX.SX! Use \input for the preamble. – TeXnician Dec 19 '18 at 10:20
• @TeXnician why would the make a difference? Isn't \include more or less just \input in the preamble anyways? – daleif Dec 19 '18 at 10:56
• @daleif I have no clue, but usually sticking to \input does reduce strange interactions, that's why I suggested it. – TeXnician Dec 19 '18 at 10:59