Arm will start to mine everything without telling it to.

As I'm walking around a world, my character will start to mine everything when I didn't say to. It acts like I have my finger pressed on the screen telling it to mine when I don't. I have to tap the screen to get it to stop. I'm playing Minecraft on a Samsung Galaxy S9+. But I also notice this happens to others using a Galaxy S9, iPhone 7 Plus, 8 Plus, and iPad.