Steps to reproduce the issue

Install current staging (2017-01-29)

Backend:

• Users > Manage > Fields > New

Title: City
Type: Text
Label: City

Required: Yes
Disabled: No
Read-Only: No

• Save

• Users > Manage > Options button > Allow User Registration > Yes

• Save

Frontend:

• Scroll down to login module > Click on Create an account

Actual result

Required field city is disabled! It's not possible to enter something.

• Fill registration form and click Register button:

Actual result

• Above a warning (which should be a red error, I think)

• All fields are empty now and user must fill them again.

Expected result

• Try again without custom field:

• Try again without custom field but with activated plugin User - Profile and a required field:

System information (as much as possible)

PHP Built On
Linux dd1620 3.13.0-107-generic #154-Ubuntu SMP Tue Dec 20 09:57:27 UTC 2016 x86_64
Database Version
5.5.52-nmm1-log
Database Collation
utf8_general_ci
Database Connection Collation
utf8mb4_general_ci
PHP Version
7.0.14-nmm1
Web Server
Apache
WebServer to PHP Interface
fpm-fcgi
Joomla! Version
Joomla! 3.7.0-beta1 dev [ Amani ] 18-January-2017 20:28 GMT
Joomla! Platform Version
Joomla Platform 13.1.0 Stable [ Curiosity ] 24-Apr-2013 00:00 GMT
User Agent
Mozilla/5.0 (Windows NT 10.0; WOW64; rv:51.0) Gecko/20100101 Firefox/51.0