Phasing Through Blocks

Sometimes you are able to walk/jump into a block and go right through it or be in it. So far it has only happened in either the nether or the end. I don't know if it's caused by a certain event, it seems to just happen randomly in other directions. Only one user can do this, not all users are affected by this (we were playing on a Realm).

Fixed By:

Logging out and going back in.