We don't have our own icons but we're using Material ones. We also provide possibility to load icons from font awesome or custom SVG icons.
There are several ways to provide the material icons in a project. I'm not sure which of them you're using. In my opinion the easiest way is to just link the material icon font in your app index.html file as described here:
https://google.github.io/material-design-icons/#icon-font-for-the-web
This would work in both dev and prod mode without any additional bundling.
If linking the material icons in the index.html file doesn't help could you please provide a simple runnable application describing the issue and we'll investigate it.