[2372] Nuxt build hangs

I've just started having a weird issue. The build command hangs after the building is done, I can see it using cpu time but the process doesn't seem to exit.

$  NODE_ENV=production ./node_modules/nuxt/bin/nuxt build
...
  nuxt:build Generating files... +8ms
  nuxt:build Generating routes... +5ms
  nuxt:build Building files... +96ms
Build completed in 76.87s

Hash:
Version: webpack 3.6.0
Time: 76889ms
... <- Chunks
Hash:
Version: webpack 3.6.0
Time: 24695ms
             Asset     Size  Chunks             Chunk Names
server-bundle.json  2.92 MB          [emitted]  
  nuxt:build Building done +2m

Get's stuck here.

It happens on my OSX dev machine and on the deployment machine (debian). Even tried removing .nuxt and node_modules and reinstalling. Not sure how I can debug this or provide more info. Is there a verbose flag?

node v8.9.3 - debian node v9.2.1 - OSX