We like to use SVG sprites
However, if you utilize a cdn or serve assets from an external source… you may run into some issues. Hopefully you find this and it saves you time that we lost figuring this out
According to MDN:
For security reasons, browsers may apply the same-origin policy on use elements and may refuse to load a cross-origin URL in the href attribute. There is currently no defined way to set a cross-origin policy for use elements.