This issue is caused by the knife going to a location the player cannot teleport to afaik, which isn't completely sound. In this case, the collision with the water caused the issue. But you can replicate it if you try to throw the knife out of bounds. Storm's Edge has some weird interactions with water and certain objects. There are [url=https://www.youtube.com/watch?v=St4aOPZxatQ]videos[/url] of you being able to get under the water in the EDZ due to the weird interactions. Best try to aim at enemies or above the ground as that's more guaranteed. Even then that doesn't work like attacking the HyperNet Current Strike boss in the final phase as it's behind a barrier.