Zoe Sleepy Trouble Bubble Goes Off Of Map

Who: Zoe Map: Summoner's Rift

When using Zoe's E and aiming at outer walls around the outside of map, the bubble will off the map and sit there. I feel that when aiming at the enclosure of the rift (top lane outer wall, bot lane outer wall, etc) the bubble should instead bounce back into the rift border.

Is this intentional?