2 Cameras: Top one doesn't render on mobile only (but colliders are still hit)

Hello,

For my opening sequence i have one camera doing a movie-like movement, and another that handles just the GUI elements. Taping the screen (or clicking) renders the GUI elements. This all works fine in Unity and on PC builds. But for mobile builds, the elements do not show.

The console will show messages indicating the touch was received and the GUI elements are now being rendered, and when I click where the "new game" should be, a new game is started as expected, but the actual graphics just don't show. Depth of the GUI camera is 5 and depth of the other camera is -1.

Again, this only happens on mobile -- works as expected everywhere else.

[Edit: When I set the top layer cameras "Clear Flags" to Solid Color it works as expected and is visible on mobile. Is there perhaps an issue w/ graphics or something? The normal game, which has much more going on, works fine, however, so I'd imagine the opening sequence should as well.]

Any idea why this could be happening?