Memory.readUtf8String returns error UTF-8 when reading strings from memory about frida-java-bridge HOT 1 OPEN

I'm getting a related, but different problem when I'm calling a method that returns a Java String BluetoothGattCharacteristic.getStringValue(). This is trying to convert it to a UTF-8 string, when the original string is an ASCII string.

This causes it to break on any UTF-8 special characters (e.g. 0xc0):

Error: can't decode byte 0xc0 in position 3
    at frida/node_modules/frida-java/lib/env.js:922
    at frida/node_modules/frida-java/lib/class-factory.js:2347
    at input:1

The code that's doing this is:

function newWriteCharacteristic(data)
{
	console.log("write: ", data.getUuid(), "\n", 
		" Data: ", shexdump(data.getStringValue(0),16));
	return this.writeCharacteristic(data);
}

Where shexdump is a simple function I stole from the Internets to convert a string to a hexdump.

from frida-java-bridge.