depth only screen corruption normal?

I have a scene with 2 UI button “P” and “Menu” and “Score: 0”, “Wave: 0” underneath in the top left nad right corner. My camera is set to depth only.

This is what isee on my phone:

Is this normal?
using solid color hides all that corruption.
happens in even blank unity3d 5.0 project.

Now that I am on my PC and looked at the screenshots a little closer, I think that you may not be using depth-only cameras correctly.

The intent is that you will have another camera with a lower depth # that your depth only camera will render on top of.

From Unity - Manual: Camera component :

If you wanted to draw a player’s gun
without letting it get clipped inside
the environment, you would set one
Camera at Depth 0 to draw the
environment, and another Camera at
Depth 1 to draw the weapon alone. The
weapon Camera’s Clear Flags should be
set to to depth only. This will keep
the graphical display of the
environment on the screen, but discard
all information about where each
object exists in 3-D space. When the
gun is drawn, the opaque parts will
completely cover anything drawn,
regardless of how close the gun is to
the wall.