Button becomes to a block when I'm close to it

I use Sony Xperia Z2a to play Minecraft. When I placed a wooden button on the wall, but when I approached it, it turned into a block of wood. I was not trapped inside the wood, and I can still see the button on the wall. Button does not disappear. The same thing happened on the stone buttons. (p.s. I use Google translate to translate what I want to say, if there are any errors, please forgive me)