On expanding transitions from Transitions box, When a condition is added in the list later while creating a behavioural script 'GameObject Transition in state' error is thrown in console. refer attached video.

Steps to repro:
1. Open attached Project
2. Project Window > Open Cube Animator > Create Empty State.
3. Create a transition New Animation > New State.
4. Inspector > Select transition > Expand.
5. Conditions > Add to List (+)
6. Add Behaviour > Add script > Create and Add
- The same issue persists for following steps
(continue from step 6)
7. Cube > Animation > Transform, Mesh renderer, Box collider

Actual Result:
'Transition in state' error is thrown on Adding behavioural script when a condition is added in list.

Expected Result:
- The behavioural script should be added without any error in console.
- Instead of flooding console with Transition in state errors more specific warning should be provided.

Occurring in:
2020.2.0a18, 2020.1.0b16, 2019.4.2f1, 2019.3.15f1, 2018.4.19f1

Environment:
Windows10 and macOS 10.15

Stack Trace:
Controller 'Cube': Transition '' in state 'New Animation' uses parameter '' which does not exist in controller.
UnityEditor.AnimationUtility:GetAnimationClips (UnityEngine.GameObject)
UnityEditorInternal.GameObjectSelectionItem:Create (UnityEngine.GameObject) (at /Users/builduser/buildslave/unity/build/Editor/Mono/Animation/AnimationWindow/GameObjectSelectionItem.cs:19)
UnityEditor.EditorWindow:Close ()
UnityEditorInternal.AddCurvesPopupHierarchyGUI:DoAddCurveButton (UnityEngine.Rect,UnityEditor.IMGUI.Controls.TreeViewItem) (at /Users/builduser/buildslave/unity/build/Editor/Mono/Animation/AnimationWindow/AddCurvesPopupHierarchyGUI.cs:75)
UnityEditorInternal.AddCurvesPopupHierarchyGUI:OnRowGUI (UnityEngine.Rect,UnityEditor.IMGUI.Controls.TreeViewItem,int,bool,bool) (at /Users/builduser/buildslave/unity/build/Editor/Mono/Animation/AnimationWindow/AddCurvesPopupHierarchyGUI.cs:42)
UnityEditor.IMGUI.Controls.TreeViewController:OnGUI (UnityEngine.Rect,int)
UnityEditorInternal.AddCurvesPopupHierarchy:OnGUI (UnityEngine.Rect,UnityEditor.EditorWindow) (at /Users/builduser/buildslave/unity/build/Editor/Mono/Animation/AnimationWindow/AddCurvesPopupHierarchy.cs:24)
UnityEditorInternal.AddCurvesPopup:OnGUI () (at /Users/builduser/buildslave/unity/build/Editor/Mono/Animation/AnimationWindow/AddCurvesPopup.cs:94)
UnityEngine.GUIUtility:ProcessEvent (int,intptr,bool&)