vagrant rsync is failing to chown

I'm using an synced folder on vagrant 1.8.1 and I want it to chown the files, but it doesn't seem to take effect. This is my synced folder:

config.vm.synced_folder(
  '../..',
  '/home/deploy/sosd/local/',
  owner: 'deploy',
  group: 'deploy',
  type: "rsync",
  rsync__chown: true,
  rsync__exclude: [
    '.git',
    '.idea',
    'src/frontend/dist',
    'src/frontend/tmp',
    'src/frontend/node_modules',
    'src/frontend/bower_components'
  ]
)

I still end up with:

drwxr-xr-x 7 vagrant vagrant 4096 Apr 21 07:39 ansible
-rw-r--r-- 1 vagrant vagrant 1198 Apr 18 10:31 circle.yml
-rw-r--r-- 1 vagrant vagrant 1202 Apr 21 05:37 README.md
-rw-r--r-- 1 vagrant vagrant  146 Apr 17 10:52 requirements.txt
drwxr-xr-x 4 vagrant vagrant 4096 Apr 14 23:15 src

Why is that?