As you can see in this image, template hierarchy limits to taxonomy-$taxonomy-$term.php.
I don’t know why a subterm falls back to taxonomy-$taxonomy.php, but I guess it searches for a taxonomy-$taxonomy-$term.php in wich $term would be workshops, science labs and so on. And since those don’t exist (I suppose), it falls back on taxonomy-$taxonomy.php.
You could make use of a workaround in your taxonomy-$taxonomy.php file wich loads the requested taxonomy-$taxonomy-$term.php file when the $term has a parent $term.