From Guild Wars 2 Wiki
Turret skills use ground targeting.
— In-game description
- Throwing a turret into a wall will cause it to stay in the wall. Most of the time it will be obstructed by the wall it is in.
- Sometimes a location will show the ground targeting symbol, but the target will have no collision. The turret will continue on its arc until it hits something with collision.
- Throwing a turret at the corner of a ledge will cause the turret to default to standing on the ledge.
- Thrown turrets are unaffected by reflection.