POST /auth/register returns {"user":null,"login":null,"ok":true}

[indr]

$ curl -H 'Content-Type: application/json' -v \
> -d '{"email":"abc@example.com"}' http://localhost:3000/auth/register
*   Trying ::1...
* Connected to localhost (::1) port 3000 (#0)
> POST /auth/register HTTP/1.1
> Host: localhost:3000
> User-Agent: curl/7.47.1
> Accept: */*
> Content-Type: application/json
> Content-Length: 27
> 
* upload completely sent off: 27 out of 27 bytes
< HTTP/1.1 200 OK
< X-Powered-By: Express
< Content-Type: application/json
< Cache-Control: private, max-age=0, no-cache, no-store
< Content-Length: 36
< Date: Mon, 01 Aug 2016 12:15:18 GMT
< Connection: keep-alive
< 
* Connection #0 to host localhost left intact
{"user":null,"login":null,"ok":true}

This happens when the seneca-user plugin is used with autopass: false option. It also happens if mustrepeat: true and only password is sent.