Metabase - webpack error when building from source in docker

When building metabase from source with docker build using the dockerfile that is provided on git, I am not able to get past the following webpack related error. I am new to webpack, babel and uglify so kinda lost here. Any direction would be great.

webpack version is 3.6.0 in package.json

ERROR in 2.bundle.js?fa2f7c1988898102e345 from UglifyJs
Invalid assignment [2.bundle.js?fa2f7c1988898102e345:1120,34]
Child html-webpack-plugin for “…/…/index.html”:
1 asset
[0] /src/node_modules/html-webpack-plugin/lib/loader.js!/src/resources/frontend_client/index_template.html 4.34 kB {0} [built]
[2] (webpack)/buildin/global.js 488 bytes {0} [built]
[3] (webpack)/buildin/module.js 495 bytes {0} [built]
+ 1 hidden module
Child html-webpack-plugin for “…/…/public.html”:
1 asset
[0] /src/node_modules/html-webpack-plugin/lib/loader.js!/src/resources/frontend_client/index_template.html 4.34 kB {0} [built]
[2] (webpack)/buildin/global.js 488 bytes {0} [built]
[3] (webpack)/buildin/module.js 495 bytes {0} [built]
+ 1 hidden module
Child html-webpack-plugin for “…/…/embed.html”:
1 asset
[0] /src/node_modules/html-webpack-plugin/lib/loader.js!/src/resources/frontend_client/index_template.html 4.34 kB {0} [built]
[2] (webpack)/buildin/global.js 488 bytes {0} [built]
[3] (webpack)/buildin/module.js 495 bytes {0} [built]
+ 1 hidden module