Regarding the Juggernaut ability, Ravage, you were likely in range when the third attack registered at the server side, but by the time the server/client showed that you got hit, your client was displaying you as having already moved out of range. Nothing to fix besides the typical server/client relationship.
Also, the game actually does what you think it should do. If a character is casting, and move out of what you would perceive as the abilities LOS, and the player does NOT move their mouse/camera to focus on you as you move, the cast WILL break. I have tested this numerous times. Therefore, you must be playing against players who have discovered this mechanic, ....when you move your mouse/camera(holding right click and changing the clients visual camera direction) you are in fact changing the direction of which the channeled ability is directing its damage.
If anyone can correct me please do,but this is what I'be come to understand about this mechanic.