I found 8 bugs.

1) MCPE does not start on a device with Android 4.4.4 (beta 16.0.0.55 and 16.0.0.57), the screen is only black.

2) The castle in the nether generates some parts far from the others and spaces of 2 by 2.

3) There is a bug in the lighting, which affects the world and the nether (16.0.0.55 and 16.0.0.57).

4) It is not possible to combine items with two clicks in Pocket mode.

5) The skin is redefined when I enter the game.

6) Very slow rendering.

7) The interface is very buggy, slow, the texts do not appear, and sometimes everything is black.

8) Rebirth point and sometimes redefined.