Problem with specular, orthographic projection, shadow amount and Android/iOS preview

I encountered a problem while I worked on a transition between a camera with a perspective projection and an orthographic projection (by reducing the FOV and move back the camera far away). All work fine on my computer (I’m working on MacOS, with Shader Model 5).

My problem is when I want to use the Android or iOS preview, it’s look like the specular reflection just stop to work when I use my orthographic projection. Is there a specific setting to set when using an orthographic projection ?

I also encounter a problem with the shadow amount setting on my directional light (movable): I’m reducing the shadow amount parameter while i’m in transition. One more time, no problem on SM5, but it just don’t work on Android/iOS. I’m missing a parameter somewhere ?