PShape setFill(indx, color) not working in Processing 4

Most appropriate sub-area of Processing 4?

OpenGL

Processing version

4.3

Operating system

MacOSX

Steps to reproduce this

"1. The source code below demonstrates the problem. The PShape should change color when the mouse is clicked.

2. The source code runs correctly in versions 2.2.1 (macos) and 3.5.4 (reported by another forum member running Windows) indicating a runtime code change prior to version 4.

3. There is a similar report from a year ago: https://github.com/processing/processing4/issues/677"

4. We would like to change the vertex colors of the original PShape object without having to create a second object.

snippet

PShape t;

void setup() {
  size(400, 400, P2D);
  surface.setTitle("Should change color when mouse clicked.");
  t = createShape();
  t.beginShape();
  t.vertex(200, 100);
  t.vertex(100, 300);
  t.vertex(300, 300);
  t.endShape(CLOSE);
  for (int i = 0; i < t.getVertexCount(); i++) {
    t.setFill(i, color(random(255), random(255), random(255)));
  }
}

void draw() {
  background(209);
  shape(t);
}

void mousePressed() {
  for (int i = 0; i < t.getVertexCount(); i++) {
    t.getVertex(i);
    t.setFill(i, color(random(255), random(255), random(255)));
  }
}

Additional context

No response

Start by tracing PShape.setFill(int, color) through the Processing 4 OpenGL path, using the supplied sketch to reproduce the behavior. Compare the current behavior with Processing 2.2.1 and 3.5.4 if available, and verify that clicking the mouse changes vertex colors on the original PShape without creating a second object.