deprecation warning on ember data models

Just updated to ember v1.12.0-beta.1 and ember-data v1.0.0-beta.16. I'm getting the following deprecation warning on the fields in my models:

DEPRECATION: Using the same function as getter and setter is deprecated. See http://ift.tt/19s4HeN for more details.

The Ember inspector Deprecations view is pointing to all my models. So I basically get one deprecation error per line in my model. Here is an example model:

import DS from 'ember-data';

export default DS.Model.extend({
    userid: DS.attr('number'),
    unitid: DS.attr('number'),
    log: DS.attr('string'),
    name: DS.attr('string'),
    start_date: DS.attr('date'),
    end_date: DS.attr('date'),
    duration_mins: DS.attr('number')
});