Those are most likely NOT hackers. The PvP in Elements is a little buggy still. What you most likely experienced is what we call desync. Desync is when your computer, and the computer of your opponent begin to show different things on each of your screens. When that happens, lots of strange things begin to occur. A common desync bug is when your opponent begins to randomly regenerate lots of health. But the ones you've stated do happen with desync.
