$datePickerFormatter.withStyle(String).format($value) Not Working

I posted a question HERE about using a Script Field for a date type. My main question was answered, but a new problem came to light.

I'm using a Script Field with a custom template and a Date Time Range Picker searcher. The custom template is as follows:

$datePickerFormatter.withStyle("MMM d, YYYY").format($value)

I'm trying to get the date output formatted like "Aug 20, 2018" using the above format string, but it's not working. In fact, no matter what string I pass to withStyle, the output is always in the same format. E.g:

$datePickerFormatter.withStyle('').format($value)
$datePickerFormatter.withStyle('MMM d, YYYY').format($value)
$datePickerFormatter.withStyle('mm:ss').format($value)
$datePickerFormatter.withStyle('dmy').format($value)

All of these format strings output the same format: 28/Aug/18 12:19 PM.

Why? And how do I get my desired format?

Jira 7.9.2