Metallic/Specular map broke fading in build

When enemies die in my game they fade instead of just disappearing and it works fine until my character have metallic/specular map attached to it. I can change values without map (for whole material) and it works good, but when i put any metallic/specular map it doesn't work anymore (shader is still switc$$anonymous$$ng to Fade but alpha is not changing at all). Also, it ONLY happens in build, it works fine in editor. How can i fix t$$anonymous$$s?

Here is my code responsible for changing material from Opaque to Fade:

         Material m = GetComponent<SkinnedMeshRenderer> ().material;
         m.SetFloat ("_Mode", 2f);
         m.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.SrcAlpha);
         m.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.OneMinusSrcAlpha);
         m.SetInt("_ZWrite", 0);
         m.DisableKeyword("_ALPHATEST_ON");
         m.EnableKeyword("_ALPHABLEND_ON");
         m.DisableKeyword("_ALPHAPREMULTIPLY_ON");
         m.renderQueue = 3000;
 
         readyToFade = true;

Here is a part responsible for actual fading (it's in Update):

             if (readyToFade) 
             {
                 Material m = GetComponent<SkinnedMeshRenderer> ().material;
                 float alpha = m.color.a;
                 Color color = new Color (1, 1, 1, 1);
 
                 if (alpha - Time.deltaTime <= 0)
                     alpha = 0;
                 else
                     alpha -= Time.deltaTime;
 
                 color.a = alpha;
                 m.color = color;
 
                 if (alpha == 0)
                     Destroy (gameObject);
             }