The custom projectiles of the Creeper's Cruel Shuriken and the Hidden Hunter's Shuriken are not flying properly. They stutter towards the target heavily and sometimes even move behind it before hitting it.

Here is a video demonstrating them, compared to the default shuriken.

Note: The default shuriken had this bug a long time ago as well. As it was fixed, it was only applied to the default one, and not to the custom ones.