Capitalization differs between simulator and device when using Gregorian.info

I found that when trying to display a string with the day and date, capitalization is different in the simulator compared to on my device (Instinct 2). In the simulator, the string shows up as "Sun, Jul 10". On the device, it is all caps: "SUN, JUL 10".

This is my code to create the string: 

var now = Time.now();
var greg_now = Time.Gregorian.info(now, Time.FORMAT_MEDIUM);
var day_date_string = greg_now.day_of_week + ", " + greg_now.month + " " + greg_now.day.toString();
var day_date_view = View.findDrawableById("DayDateLabel") as Text;
day_date_view.setText(day_date_string);

Here's the relevant line of layout.xml:

<label id="DayDateLabel" x="96" y="17" font="Graphics.FONT_XTINY" justification="Graphics.TEXT_JUSTIFY_RIGHT" color="Graphics.COLOR_WHITE" />

I am using Connect IQ 4.1.4.