Post dates in other languages cause strange dates shown

WP RElated Posts
Version 3.6

There is a problem with sites that have dates shown in another languages than english. The problem is that by the time the post lists reach the wp_rp_generate_related_posts_list_items function they may come from different queries and some return the ISO dates, and some return the englsih/Language date. The latter will mess up the mysql2date function.

see examples:

<!-- stdClass::__set_state(array(
   'ID' => 'in_66504',
   'post_url' => 'http://www.film-tv-video.de/productions/2015/10/03/dji-produzierte-multikopter-aufnahmen-vom-oktoberfest/',
   'thumbnail' => 'http://www.film-tv-video.de/wp-content/uploads/2016/02/B_1015_Oktoberfest_5-150x150.jpg',
   'post_title' => 'DJI produzierte Multikopter-Aufnahmen vom Oktoberfest',
   'post_excerpt' => '',
   'post_content' => '',
   'post_date' => '3. October 2015',
   'comment_count' => 0,
   'picked' => true,
   'type' => 'own_sourcefeed',
   'pos' => 3,
)) -->

<!-- stdClass::__set_state(array(
   'ID' => 'in_63893',
   'post_url' => 'http://www.film-tv-video.de/equipment/2015/01/09/dji-zeigt-handheld-mount-fur-eigene-4k-kamera/',
   'thumbnail' => 'http://www.film-tv-video.de/wp-content/uploads/2016/02/B_0115_DJI_Handgriff-150x150.jpg',
   'post_title' => 'DJI zeigt Handheld-Mount für eigene 4K-Kamera',
   'post_excerpt' => 'Mit einem neu vorgestellten Griff können Kamera und Stabilizer der Flugdrohne Inspire 1 von DJI nun auch im Handheld-Modus genutzt werden.',
   'post_content' => '',
   'post_date' => '2015-01-09 00:00:00',
   'comment_count' => '0',
   'picked' => true,
   'type' => 'own_sourcefeed',
   'pos' => 0,
)) -->

UNRELATED STUFF: It would be nice to be able to customize the “Posted in” text for the category display

https://wordpress.org/plugins/wordpress-23-related-posts-plugin/