Thank you for reporting the issue. After looking into it, we've found that the broken masking you experienced is related to a system incompatibility with WebGL. It seems that your computer's GPU may not be fully supporting WebGL, which is why the visual issue is happening.
As a workaround, I recommend checking if your system supports WebGL properly or if it is falling back to Canvas, which might not support masking the same way. You could also try updating your GPU drivers or adjusting system settings to better handle WebGL.