lstinline puts space before dot

I am trying to use lstinline to style filenames in my document, but it puts some random whitespace befor the dot. I presume it has to do with autosettings for punctuation?

Can I deactivate this with listings or is it a generall Latex Thing?

MWE:

documentclass[11pt]{scrreprt}
usepackage{color}
usepackage{listings}
lstset{basicstyle=color{blue}} % just to demo

begin{document}

    I use the file lstinline{file.ext}, which is nice.

end{document}

documentclass[11pt]{scrreprt}
usepackage{color}
usepackage{listings}
lstset{basicstyle=color{blue}ttfamily}

begin{document}

    I use the file lstinline{file.ext}, which is nice.

end{document}

documentclass[11pt]{scrreprt}
usepackage{color}
usepackage{listings}
lstset{
    basicstyle=color{blue},
    alsoletter={.}
} % just to demo

begin{document}

    I use the file lstinline{file.ext}, which is nice.

end{document}