I am seeing the following notice when installing the 3.1 site via the browser. Found when testing https://tracker.moodle.org/browse/MDL-53717.

Notice: Undefined property: stdClass::$timezone in /home/jake/moodledata/v31_tmp/moodle/lib/classes/user.php on line 340

This occurs at the top the following page:

http://localhost/v31_tmp/user/editadvanced.php?id=2

and impacts the automatic redirect after saving the admin user record.

You'll need to add these lines to the config.php for the instance to see the notice:

@error_reporting(E_ALL | E_STRICT); // NOT FOR PRODUCTION SERVERS!
@ini_set('display_errors', '1'); // NOT FOR PRODUCTION SERVERS!
$CFG->debug = (E_ALL | E_STRICT); // === DEBUG_DEVELOPER - NOT FOR PRODUCTION SERVERS!
$CFG->debugdisplay = 1; // NOT FOR PRODUCTION SERVERS!

This bug was not found in 3.0.3-Integration or 2.9.5-Integration.