When I enter water, the on screen directional pad vanishes. It continues to respond to my touch, but it becomes invisible. Swimming across the surface creates a flickering effect.
Hardware is Samsung Galaxy Note tablet.
Issue persists when fancy graphics and/or animated water is turned off. When the render distance is turned to minimal, the flickering when swimming on the top persists, but the d-pad remains visible when underwater.

What I expected to happen was...:
GUI would remain visible whether swimming or not.

What actually happened was...:
GUI vanishes and flickers, although inventory bar seems to be unaffected.

Steps to Reproduce:
1. For full vanishing effect, render distance should be set to maximum and tester should stand on a block one block below the surface of the water. Any movement in water on any setting seems to produce the flickering.

The first screenshot is standing on land, the second in water. No settings have been changed between them.