Transparent object issue in Edge Detection image effects

I use Unity standard assets' edge detection image effects.On win 7 PC,it looks alright in Editor and Game Window. The scene is simple,some opaque geometries with standard shader,one directional light,a transparent plane mesh partially inserted in the ground.Also,I intentionally add a diffuse fallback to the transparent shader,so it has shadows.As below shows:

But when built into iOS,the transpareny object's sorting order goes wrong.It looks like the transparent object are rendered after the image effects process and it is above all other objects,as below shows:

Why is that,and how to solve this problem?Thanks!