Processing bug?

Processing
21

You could also just change the code in the OP to -

PGraphics v;

void setup() {
  size(300, 300, P2D);
  v = createGraphics(260, 200, JAVA2D);
  updateBuffer();
}

void draw() {
  background(200, 200, 255);
  image(v, 20, 20);
}

void updateBuffer() {
  v.beginDraw();
  v.background(255);
  colorMode(HSB, 360, 100, 100);
  int c = color(300, 100, 100); //NO  'unexpected token:.' runtime error?
  colorMode(RGB, 255, 255, 255);
  v.fill(c);
  v.noStroke();
  v.ellipse(130, 100, 130, 100);
  v.endDraw();
}

I’m not saying it’s ideal, but it’s not a requirement to be able to use color with an offscreen graphics (unless you’re getting into threading)