Releasing render texture that is set error thrown on changing Image SubLayer index in Render Schedule.

Steps to repro:
1. Create a new HDRP template project.
2. Windows > Render Pipeline > Graphics Compositor Window.
3. Enable Compositor > Render Schedule > Select New SubLayer.
4. Add Image SubLayer > Drag to the Top of the list.

Actual Result:
Releasing render texture that is set error thrown in the console.

Expected Result:
No error in the console.

Reproducible in:
2021.1.0a4, 2020.2.0b10, 2020.2.0b8 with Package version 10.1.0.

Working Fine in:
2020.2.0b9, 2020.2.0b8 with Package version 10.0.0-preview.27.

Environment:
Occurring on Windows 10 & mac 10.15.

Stack trace:
Releasing render texture that is set as Camera.targetTexture!
UnityEngine.GUIUtility:ProcessEvent (int,intptr,bool&)