Editor crashes on changing Tile anchor in tile palette prefab while tile palette painter is in edit mode.

Steps to repro:
1. Open the attached project.
2. Windows > 2D > Tile Palette.
3. Click on Edit > Change any Tile position.
4. Open "Raised" Tile Palette in prefab mode > Select Layer1.
5. Change Tile anchor property X to 1 > Enter.

Actual Result:
Editor crashes on changing Tile anchor in tile palette object.

Expected Result:
Tile anchor property changes.

Reproducible in:
2020.2.0a3, 2020.1.0b2, 2020.1.0a14,

Working fine in:
2020.1.0a13.

Environment:
Occurring on Windows 10 & Mac 10.14.

Stack trace:
========== OUTPUTTING STACK TRACE ==================

0x00007FF75722508A (Unity) SetupPrefabInstancesAndFileIDsForSaveFromMatchingObjects
0x00007FF75722117A (Unity) SavePrefab_Internal
0x00007FF75721FCC3 (Unity) SaveAsPrefabAsset
0x00007FF756AEB1D3 (Unity) PrefabUtilityBindings::SaveAsPrefabAsset_Internal
0x00007FF757AAA2DB (Unity) PrefabUtility_CUSTOM_SaveAsPrefabAsset_Internal
0x0000027E30D7A373 (Mono JIT Code) (wrapper managed-to-native) UnityEditor.PrefabUtility:SaveAsPrefabAsset_Internal (UnityEngine.GameObject,string,bool&)
0x0000027E30D7A2C3 (Mono JIT Code) UnityEditor.PrefabUtility:SaveAsPrefabAsset (UnityEngine.GameObject,string,bool&)
0x0000027E30D79EBB (Mono JIT Code) UnityEditor.Experimental.SceneManagement.PrefabStage:SavePrefab ()
0x0000027E30D789CB (Mono JIT Code) UnityEditor.Experimental.SceneManagement.PrefabStage:Save ()
0x0000027E30D7883D (Mono JIT Code) UnityEditor.Experimental.SceneManagement.PrefabStage:AutoSave ()
0x0000027E30D5E163 (Mono JIT Code) UnityEditor.Experimental.SceneManagement.PrefabStage:HandleAutoSave ()
0x0000027E30D5DDF3 (Mono JIT Code) UnityEditor.Experimental.SceneManagement.PrefabStage:Tick ()
0x0000027E2F6450D9 (Mono JIT Code) UnityEditor.SceneManagement.StageNavigationManager:ValidateAndTickStages (bool)
0x0000027E2F644DCB (Mono JIT Code) UnityEditor.SceneManagement.StageNavigationManager:Update ()
0x0000027DC945C112 (Mono JIT Code) (wrapper delegate-invoke) <Module>:invoke_void ()
0x0000027E2F63876C (Mono JIT Code) UnityEditor.EditorApplication:Internal_CallUpdateFunctions ()
0x0000027E30ACB62D (Mono JIT Code) (wrapper runtime-invoke) object:runtime_invoke_void (object,intptr,intptr,intptr)
0x00007FFFB3F0CDA0 (mono-2.0-bdwgc) [c:\build\output\unity-technologies\mono\mono\mini\mini-runtime.c:2809] mono_jit_runtime_invoke
0x00007FFFB3E92112 (mono-2.0-bdwgc) [c:\build\output\unity-technologies\mono\mono\metadata\object.c:2921] do_runtime_invoke
0x00007FFFB3E9B10F (mono-2.0-bdwgc) [c:\build\output\unity-technologies\mono\mono\metadata\object.c:2968] mono_runtime_invoke
0x00007FF75616D884 (Unity) scripting_method_invoke
0x00007FF7561673CB (Unity) ScriptingInvocation::Invoke
0x00007FF7561610B5 (Unity) ScriptingInvocation::Invoke<void>
0x00007FF754A66EA2 (Unity) Scripting::UnityEditor::EditorApplicationProxy::Internal_CallUpdateFunctions
0x00007FF756D33462 (Unity) Application::TickTimer
0x00007FF75750B29C (Unity) MainMessageLoop
0x00007FF75751497E (Unity) WinMain
0x00007FF7591365D6 (Unity) __scrt_common_main_seh
0x00007FF8097B7BD4 (KERNEL32) BaseThreadInitThunk
0x00007FF80A5ECED1 (ntdll) RtlUserThreadStart

========== END OF STACKTRACE ===========