ArchLinux, as a bleeding-edge distribution, tends to be fairly-well caught up.
I would recommend you install the distro package (which is kept up-to-date) over the AUR package (which is calibre-git) but
this bug has still not been fixed -- I am rather disappointed.
Hey, cool -- the AUR package does not have this problem...
Anyway, yeah -- there are instances where calibre will not do what it is supposed to do, if using the official calibre package.