These errors appear in the console when following the Creator Kit: Puzzle tutorial, or making a new project with the 3d with extras template:

IndexOutOfRangeException: Invalid kernelIndex (1) passed, must be non-negative less than 4.
UnityEngine.Rendering.PostProcessing.MultiScaleVO.PushRenderCommands (UnityEngine.Rendering.CommandBuffer cmd, System.Int32 source, System.Int32 destination, UnityEngine.Vector3 sourceSize, System.Single tanHalfFovH, System.Boolean isMSAA) (at Library/PackageCache/com.unity.postprocessing@2.3.0/PostProcessing/Runtime/Effects/MultiScaleVO.cs:371)
UnityEngine.Rendering.PostProcessing.MultiScaleVO.GenerateAOMap (UnityEngine.Rendering.CommandBuffer cmd, UnityEngine.Camera camera, UnityEngine.Rendering.RenderTargetIdentifier destination, System.Nullable`1[T] depthMap, System.Boolean invert, System.Boolean isMSAA) (at Library/PackageCache/com.unity.postprocessing@2.3.0/PostProcessing/Runtime/Effects/MultiScaleVO.cs:172)
UnityEngine.Rendering.PostProcessing.MultiScaleVO.RenderAfterOpaque (UnityEngine.Rendering.PostProcessing.PostProcessRenderContext context) (at Library/PackageCache/com.unity.postprocessing@2.3.0/PostProcessing/Runtime/Effects/MultiScaleVO.cs:505)
UnityEngine.Rendering.PostProcessing.PostProcessLayer.BuildCommandBuffers () (at Library/PackageCache/com.unity.postprocessing@2.3.0/PostProcessing/Runtime/PostProcessLayer.cs:570)
UnityEngine.Rendering.PostProcessing.PostProcessLayer.OnPreCull () (at Library/PackageCache/com.unity.postprocessing@2.3.0/PostProcessing/Runtime/PostProcessLayer.cs:462)
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr, Boolean&)

Reproduction steps:
- create a new project with the 3d with extras template
- notice the console
- if you clear the console but focus the Game Window, error reappears instantly
- error still spams console even after going into play mode

Reproducible with: 2020.1.0a24, 2020.1.0b5, 2020.2.0a5 (2.3.0)
Not reproducible with: 2019.3.0a5, 2020.1.0a23 (2.3.0)

Cannot reproduce this by simply adding the PostProcessing package to a new project made with the 3D Template and making a new PostProcessing effect.

There are 2 workarounds for this:
1 - reimport the project - or delete the Library folder and restart the project.
2 - delete the libcache folder - [Unity installation folder]\Unity\2020.1.0b8\Editor\Data\Resources\PackageManager\ProjectTemplates\libcache