So I'm trying to finish my master's thesis with the leadsheets package. So far everything works fine, but I seem to not being able to get "major13" chords to display correctly as superscripted "maj13" as it is the case with "major7" and "major9". I tried to create a minimal example using the template with which I work. I am - as you can probably see - not very familiar with LaTex or programming at all, but I hope that this is a minor problem to be quickly fixed, even by an unexperienced beginner. Thank you for your help!
%% LyX 2.3.4 created this file. For more info, see http://www.lyx.org/.
%% Do not edit unless you really know what you are doing.
\documentclass[12pt,oneside,ngerman,a4paper,titlepage,12pt,numbered]{PhDThesisLyX}
\usepackage[T1]{fontenc}
\usepackage[latin9]{luainputenc}
\usepackage{fancyhdr}
\pagestyle{fancy}
\setcounter{secnumdepth}{3}
\setcounter{tocdepth}{3}
\usepackage{setspace}
\usepackage[authoryear]{natbib}
\onehalfspacing
\makeatletter
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% User specified LaTeX commands.
\usepackage{leadsheets}
\useleadsheetslibraries{chords}
\makeatother
\usepackage{babel}
\begin{document}
\chapter{minimal example}
\writechord{Fmaj7} - is what I want; \writechord{Cmaj13} - is what I get
\end{document}