clef change strange spacings

[eroux]

In the following minimal example:

\documentclass[12pt]{article}
\usepackage{libertine}
\usepackage[autocompile]{gregoriotex}
\begin{document}
\gabcsnippet{(c3) {u}uuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu(g) (z0;c3) ut(h)}
\end{document}

resulting in

the spacing is completely odd, the custo starts at the end of the text, while the spacing algorithm should be similar to the new bar spacing algorithm