migration open gl es 2 in android 7

hi i'm porting my simple videogame based of open gl es 2 in a different smartphone (galaxy j7):
it works fine with Galaxy note 2 (open gl es 2 and android 4.2) , bad in Galaxy j7 (open gl es 3.1 and android 7)
when I draw two geometries 3D one above the other  something goes wrong

I've posted  the bad effect in this video youtube (look for with google)  youtu.be/xJHfKASQ-7k

while this is a screeshot about note2  in          youtu.be/ERljT0O3vW4

 i use the code
        glView = new GLSurfaceView(this);
        glView.setRenderMode(GLSurfaceView.RENDERMODE_WHEN_DIRTY);
      
       and every 30 mills I call glView.requestRender()

Perhaps in android 7 `rendermode_with_dirty` doesn't work? or different settings/instruction open gl are needed?

1)in the draw method of the game loop
        GLES20.glClearColor(0, 0, 0, 1);
      GLES20.glEnable(GLES20.GL_DEPTH_TEST);
   GLES20.glClearDepthf(1.0f);
      GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT | GLES20.GL_DEPTH_BUFFER_BIT);   
     (draw goemetries)

        GLES20.glFlush();  
  

2)for each geometry 3d I do

GLES20.glEnable(GLES20.GL_CULL_FACE);
GLES20.glDisable(GLES20.GL_BLEND);
GLES20.glDepthMask(true);
(load program -shader etc - etc..)
GLES20.glDisable(GLES20.GL_CULL_FACE);