UnitTypes in training queues are not matching static unit types

[Bytekeeper]

This simple example for Protoss builds a probe and checks if the unit type in the training queue is actually a probe. It's toString() returns probe but it is another object:

import bwapi.*;

public class UnitTypeBug extends DefaultBWListener {
    private Mirror mirror = new Mirror();
    private Game game;
    private Player self;

    public void run() {
        mirror.getModule().setEventListener(this);
        mirror.startGame();
    }

    @Override
    public void onStart() {
        game = mirror.getGame();
        self = game.self();
    }

    @Override
    public void onFrame() {
        for (Unit u: self.getUnits()) {
            if (!u.getTrainingQueue().isEmpty()) {
                if (u.getTrainingQueue().get(0) != UnitType.Protoss_Probe) {
                    System.err.println("Unit type mismatch");
                }
            }
            if (!u.isTraining() || u.canTrain(UnitType.Protoss_Probe)) {
                u.train(UnitType.Protoss_Probe);
            }
        }
    }

    public static void main(String[] args) {
        new UnitTypeBug().run();
    }
}

It should not print "Unit type mismatch", but it does,