Processing bug?

Processing
10 
/**
 * Threaded color() Access Test (v1.0)
 * GoToLoop (2018/Dec/13)
 * https://Discourse.Processing.org/t/processing-bug/6561/10
 */

// Blinks magenta from time to time:
static final String THREADED_METHOD = "colorThreadBug";

// Always blue background():
//static final String THREADED_METHOD = "colorThreadWorkaround";

void setup() {
  size(300, 200);
  thread(THREADED_METHOD);
}

void draw() {
  background(#0000FF);
  getSurface().setTitle("Frames: " + frameCount);
}

void colorThreadBug() {
  for (;; delay(1))  color(#FF0000);
}

void colorThreadWorkaround() {
  final PGraphics offscreenColor = createGraphics(0, 0);
  final java.lang.reflect.Method colour;

  try {
    colour = PGraphics.class.getMethod("color", int.class);
  }
  catch (final NoSuchMethodException e) {
    throw new RuntimeException(e);
  }

  try {
    for (;; delay(1))  colour.invoke(offscreenColor, #FF0000);
  }
  catch (final ReflectiveOperationException e) {
    throw new RuntimeException(e);
  }
}