Theme Check reporting an incorrect theme slug and text domain

I was running my theme through Theme Check to check for WP.org compliance and it is giving me a warning that the theme is in the wrong directory. The specific warning is below:

WARNING: Your theme appears to be in the wrong directory for the theme name. The directory name must match the slug of the theme. This theme's correct slug and text-domain is the-m-x.

However, my theme's text domain is set to the-mx, without the dash in between.

In style.css, I have:

/*
Theme Name: The M.X.
...
Text Domain: the-mx
*/

In functions.php:

function the_mx_setup() {
...
load_theme_textdomain( 'the-mx', get_template_directory() . '/languages' );
...
?

I am trying to figure out why the theme's slug is coming up as the-m-x instead. Also, would this prevent a theme from passing review?