The location bug seems to happen mainly with patrolling mobs. You will see the mob in one position but when you leap, you leap to the mobs actual location. Your computer will tell you you are out of range since it thinks the mob is still in the original position, not where your leap put you.
Some things you also have to be aware of, in some places you cannot target/fight through a doorway/opening, in some places your companion will not cross that same type of threshold (you need to put them away and recall them), and elevators cause companions to bug all the time
You will find where these locations are by trial and error, and in some cases people exploit them (especially flash points).