Hints

1) If target is moved using physics methods (eg. AddForce) and trails are not smooth enough, enable Rigidbody interpolation setting.

Also make sure physics methods are used in FixedUpdate().

2) If trails do not render correctly in deferred rendering path, call ClearStencilAfterLightingPass. See: https://docs.unity3d.com/2019.3/Documentation/ScriptReference/Camera-clearStencilAfterLightingPass.html