Fingerprinting exception in glimmer component not working

I have a fingerprint exception array in ember-cli-build ( ember.js 3.16.1)

 fingerprint: {
	ignore: ['assets/images/','assets/arp/page_images/','assets/arp/ui_images/','data-articad2/' ],
exclude: ['assets/images/','assets/arp/page_images/','assets/arp/ui_images/','data-articad2/']

All the paths in assets/arp/page_images seem to work fine, the images come out, because they are not finger-printed and they are referenced in a classic ember component.

However the images in “assets/images” are not finger-printed either, but yet the src attribute in the img tag that points to this location has been finger-printed so it results in missing images, in the production build only.

The template code that has finger printing is like this:

>  {{#if @category.categoryIsOpen}}
>             <img src="{{root-url}}assets/images/down.png"/>
>   {{else}}
>             <img src="{{root-url}}assets/images/up.png"/>
>   {{/if}}

When I look in the inspector on running a production build, the down and up images have been given a finger-print on them, so it links to non-existent image. Yet the image itself has not been finger printed, in the dist/assets/images folder.

I’m wondering if it’s broken because it’s in a glimmer component within a classic Ember component? If there anything else I’m missing