Event system on android mobile first touch animation hiccup.

Hi

Im trying create lite game menu with new UI in Unity 5. Background is image script, animated sun rays are image script and sun is button. If I run application in editor everything looks great but If I run it on android mobile device and press button or tap the screen only first time I can see animation hiccup on sun rays, maybe FPS drops. Every next touch is ok. It seems like gc or invoke issue in event system. If I turn of event system and add box collider trigger on button image and write script it works great on mobile device too, but I want to use Event system. How can I fix it? By the way can I use new UI event system to control player character on android mobile device or is better to use collider triggers on UI images?better to use collider triggers on UI images?