register_taxonomy('query_var'=>true) causing empty media library

Normally after looking up source code, or googling I can figure these things out, but this one has me scratching my head…

register_taxonomy() with $args with 'query_var' => true in my themes functions.php is causing an empty pop-up media library page that usually shows all my files..

Playing around in the source code, I found that when I set 'query_var' => true, the array that prints the media items ($GLOBALS['wp_the_query']->posts in get_media_items() in media.php) is empty, instead of the 100s of posts that show when query_var => false

As I do need to query the var on the site, but not the admin, I’ve made this bandaid solution:

$queryvar = (is_admin()) ? false : true;

register_taxonomy( ... , ... , array(
	...
	'query_var' => $queryvar,
	...
));

But I’ve found lots of people online with the same issue, but no resolve on any threads, so my snippet above might be of help- but if anyone could shed some light on what’s going on that’d be great.