I think setting the public path to setPublicPath(‘/app/themes/sage-theme/public/’) would work but the problem is the URLs from acorn & the URL from setPublicPath is conflicting and it is doubling the URL. I’m still trying to figure this out and use some hooks base on the roots bud docs but still out of luck 
Kindly see the reference for conflicting URLs:
e class='quote' data-post="1" data-topic="22186">
Bud v5.2.0 has been released A big change for dependency management with a couple very important bug fixes. Deprecations setPublicPath (when using @roots/sage) bud.setPublicPath is deprecated when using the @roots/sage preset. Setting the public path in roots/sage will break builds now that it is no longer needed (it’ll end up doubling up URLs in Acorn). We know that’s annoying so @roots/sage (the extension) overrides setPublicPath with a function that intentionally lets the passed value …