An unknown version of wordpress (4.1.8) ?

Hello there,
This morning was a normal day, with the usual updates.

Checking WP versions of all my sites (I wrote a small bash script that does this for me), I was surprised to discover some WP 4.1.8 ...

I have checked three times before coming to ask here ...
4.1.8 No, nowhere ...

And yet:

#cat wp-includes/version.php
 * The WordPress version string
 * @global string $wp_version
$wp_version = '4.1.8';

I have more than a dozen sites like that.
You would have an idea of what is happening with my WP?

Thank you.