Unable to post boolean to nested field

I have a OneToOne field to the user and a boolean: https://git.startinblox.com/djangoldp-packages/djangoldp-notification/blob/master/djangoldp_notification/models.py#L58-60

I want to change this boolean.

When I post directly to /settings/xyz/, it works fine.

When I post to /users/xyz/, {settings: {"@id": "/settings/xyz/, "receiveMail": false}}, it does not work.

With other kind of fields, like on djangoldp-profiles, it works fine.

Related jsbin: https://jsbin.com/luneleveva/1/edit?html,output