Standard Assets disappears in somes Android Phones

First than nothing: My english not is very good.

Well, I'am doing a basic 3d game to learn Unity, i'm trying do a game of a ball moved by the MobileJoystick, in the editor it works but when i try it in my phone (Samsumg Galaxy S6) , when I touch it the MobileJoystick this dissapears. i tried several times but the same. now i trying it in an Samsumg Galaxy S7 and here it works very good, and a Huawey y520 too, but in a LG L620 don't work how in my phone.

How can i repair this and this does not hapend any phone?

(Sorry for my English :/)