Just to inform that in GlotPressGlotPress GlotPress is the translation management software that powers Translate.WordPress.org. More information is available at glotpress.org. the sub-folder for 2013 is not the theme domain twentythirteen as other official themes (2010, 2011, 2012)
but an annoying ‘-‘ is inside
https://translate.wordpress.org/projects/wp/dev/twenty-thirteen
Please erase this ‘-‘, it will facilitate automatic downloading updated .moMO files MO, or Machine Object is a binary data file that contains object data referenced by a program. It is typically used to translate program code, and may be loaded or imported into the GNU gettext program. This is the format used in a WordPress install. These files are normally located inside …/wp-content/languages/ according theme domain
Hope you will find the good contact to fixe this