Unable to add Reference keys with ArgumentOutOfRangeException in the Recorder Bindings component.

Steps to repro:
1. Create a new HDRP template project.
2. Windows > Package Manager > Recorder 3.0.0-pre.1 > Install.
3. Create an Empty game object.
4. Inspector > Add Component > Recorder Bindings.
5. Add Keys to the list.

Actual Result:
-Unable to add Reference keys.
-ArgumentOutOfRangeException error in the console.

Expected Result:
Reference keys should be added without any errors in the console.

Reproducible in:
2021.2.0a17, 2021.1.8f1, 2020.3.9f1, 2019.4.21f1 with Package version 3.0.0-pre.1, 2.5.4.

Environment:
Occurring on Windows 10 & Mac 10.15.

Stack trace:
ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index
System.ThrowHelper.ThrowArgumentOutOfRangeException (System.ExceptionArgument argument, System.ExceptionResource resource) (at <695d1cc93cca45069c528c15c9fdd749>:0)
System.ThrowHelper.ThrowArgumentOutOfRangeException () (at <695d1cc93cca45069c528c15c9fdd749>:0)
System.Collections.Generic.List`1[T].get_Item (System.Int32 index) (at <695d1cc93cca45069c528c15c9fdd749>:0)
UnityEngine.Recorder.SerializedDictionary`2[TKey,TValue].OnAfterDeserialize () (at library/packagecache/com.unity.recorder@2.5.5/runtime/serializeddictionnary.cs:36)
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr, Boolean&)