Source Maps not Appearing in Chrome Dev Tools on `ionic serve`

Ionic Framework ionic-v3
3

I have also noticed that source maps are not appearing for me. Both on Chrome and Firefox on MacOS

$ ionic info

global packages:

    @ionic/cli-utils : 1.4.0
    Ionic CLI        : 3.4.0

local packages:

    @ionic/app-scripts              : 1.3.7
    @ionic/cli-plugin-ionic-angular : 1.3.1
    Ionic Framework                 : ionic-angular 3.4.2

System:

    Node       : v7.10.0
    OS         : macOS Sierra
    Xcode      : Xcode 8.3.3 Build version 8E3004b 
    ios-deploy : not installed
    ios-sim    : not installed
    npm        : 4.2.0