D8 – Bootstrap subtheme conditional-stylesheets

i’ve set the conditional-stylesheets settings in my info.yml file to spec (as per https://www.drupal.org/comment/reply/2659496) and cleared my caches, but there is no reference to my IE stylesheet in the browser. Made sure Drupal & browser cache cleared too, I even thought about the css file limit in IE and reduced to 20 files, and even tried turning on aggregation. no luck.

Drupal version: 

Source: https://www.drupal.org/taxonomy/term/3/feed