Animated scaling discrepancies with openfl-disable-graphics-upscaling flag

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Animated scaling of vector shapes behaves very differently when the openfl-disable-graphics-upscaling is set.

This code draws a circle and animates its scale:

package;

import openfl.display.Shape;
import openfl.display.Sprite;
import openfl.display.StageScaleMode;
import motion.Actuate;
import motion.easing.Linear;

class Main extends Sprite {

  private static inline var CACHE_AS_BITMAP = true;
  private static inline var START_AT_ZERO = true;
  private static inline var USE_AS_MASK = false;

  private static inline var WIDTH = 500;
  private static inline var HEIGHT = 500;

  public function new() {
    super();

    stage.scaleMode = StageScaleMode.NO_SCALE;

    graphics.beginFill(0x0000ff);
    graphics.drawRect(0, 0, WIDTH, HEIGHT);
    graphics.endFill();

    var circle = new Shape();
    circle.graphics.beginFill(0xff0000);
    circle.graphics.drawCircle(0, 0, 100);
    circle.graphics.endFill();
    circle.scaleX = circle.scaleY = 1;
    circle.cacheAsBitmap = CACHE_AS_BITMAP;
    
    addChild(circle);
    circle.x = WIDTH / 2;
    circle.y = HEIGHT / 2;

    if (USE_AS_MASK) {
      this.mask = circle;
    }

    Actuate
      .update(
        val -> circle.scaleX = circle.scaleY = val, 
        1, 
        [ START_AT_ZERO ? 0 : 0.1 ], 
        [ 1 ]
      )
      .ease(Linear.easeNone);
    
  }
}

Without the openfl-disable-graphics-upscaling flag, it behaves as expected for all values of the constants CACHE_AS_BITMAP, START_AT_ZERO, and USE_AS_MASK:

Set openfl-disable-graphics-upscaling, though, and things get weird. Different values of CACHE_AS_BITMAP, START_AT_ZERO, and USE_AS_MASK generate very different results.

With START_AT_ZERO = true, nothing ever renders. I expect this is because the bitmap is generated with scale of 0, despite having set scaleX and scaleY to 1 earlier:

With START_AT_ZERO = false and CACHE_AS_BITMAP = true, the circle is cached with scale 0.1 and scaled up from there. This is alright, but I would expect the cached bitmap to be of the initial scale of 1:

With START_AT_ZERO = false and CACHE_AS_BITMAP = false, scaling doesn't work at all. Instead, we get translation of the circle scaled to 0.1:

Further, with USE_AS_MASK = true then we always get the translation behaviour, regardless of the CACHE_AS_BITMAP value:

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Any information on this at all? It's blocking me from implementing some optimizations that I need for release.