Unity2D quads not appearing in front of other quads in Android build

I have multiple Quads in my scene serving as buttons and a background. One is called "GameOver Overlay" which is the background, and I have two colored quads that serve as buttons. All three quads are children of an empty "GameOver Screen" object.

The Camera has a Z value of -10.
The GameOver Overlay has a Z value of 0.
The button quads have Z values of -2.

According to those Z values, the buttons should appear in front of the overlay. And they do in the editor, and also in a standalone build.
However, when I switch platform to Android, the buttons appear in front in the editor, but when I build and run it on my Android device, the buttons appear behind the Overlay. I've had trouble with other GameObjects in the same scene, but I have solved it by just moving it out of the camera space. However, I can't do that with this.

Check out these screenshots of the problem: This is the editor.

And this is a screenshot of my Android device.

Does anyone know what is causing this? Thanks for the help in advance!