[Help] Changing stock icons using Nova launcher

Having trouble changing the stock apps icons using nova launcher (such as messages, phone) when I change the icon pack using the nova launcher.

The rest of the apps that have icons change, but not these ones. I know I can go through and manually change them, but is there a way to do this automatically? Am I missing a setting somewhere?

Thanks for your help

Edit: so it appeared to be the icon pack itself, was trying with glyphicons, or a white icon pack and didn't work. Switched to using Delta and it was fine. Not sure what caused it or fixed it but thanks!