Phaser 3.24.0 canvas Mask not working on img within a container

Phaser 3
1

hello. an curious question, why mask is not working on object added on a container.

this only happen when using canvas render mode.

webgl object within a container
image

canvas object within a container
image

canvas object outside of container
image

2

Probably a WebGL Only feature. A lot of intensive shader thingies are not supported for Canvas.

3

Bitmap masks are WebGL only.

4

it’s geometry mask made from graphic rectangle