Scrollview Viewport Mask not hide content

I've seen other threads about this issue, and it could also be a bug.

The Scroll View contains only UI elements (Image, Text, Button, Panel, and anyway I need to scroll these components) and has a white-transparent Image source. But even putting it in full color the result does not change.
In Viewport the Mask component has ShowMaskGraphic on, even if I ignore the utility of ShowMaskGraphic.

Problem: in Unity everything works perfectly. Compiled for Android the Content is all visible, even outside the Viewport.

I have at least two Scroll Views in my game, and both have this flaw.

Platform changes the result!

Have you tried a build on desktop? It can be related to the fact that it is a build OR the fact that it is on android.

On Windows it works correctly. But I need it to work on Android too!

I have come to the conclusion that this is a bug. Updated label

I´m having this same bug too, unity 2021.1.6f1, all fine on editor, but on android, both Il2CPP and mono, it doesn't clip/mask.

@xtdiwd , did you sent a bug report?