The callstack looks like this:

ActiveEditorTracker::ForceReloadInspector
SceneTracker::ForceReloadInspector
RefreshInternalV2
StopAssetImportingV2
CreateSerializedAssetV2
AssetDatabase::CreateSerializedAsset
AssetDatabaseBindings::CreateAsset
AssetDatabase_CUSTOM_CreateAsset
(wrapper managed-to-native) UnityEditor.AssetDatabase:CreateAsset (UnityEngine.Object,string)
[D:\MiFBox\Unity\New Unity Project\Assets\TestScript.cs:17] TestScript/TestScriptEditor:OnDisable ()
(wrapper runtime-invoke) object:runtime_invoke_void__this__ (object,intptr,intptr,intptr)
[c:\build\output\unity-technologies\mono\mono\mini\mini-runtime.c:2809] mono_jit_runtime_invoke
[c:\build\output\unity-technologies\mono\mono\metadata\object.c:2921] do_runtime_invoke
[c:\build\output\unity-technologies\mono\mono\metadata\object.c:2968] mono_runtime_invoke
scripting_method_invoke
ScriptingInvocation::Invoke
ScriptingInvocation::InvokeChecked
SerializableManagedRef::CallMethod
MonoBehaviour::WillDestroyComponent
DestroyObjectHighLevel_Internal
DestroyObjectHighLevel
ActiveEditorTracker::Element::~Element
std::vector<ActiveEditorTracker::Element,std::allocator<ActiveEditorTracker::Element> >::clear
ActiveEditorTracker::Rebuild
ActiveEditorTracker::DidFlushDirty
SceneTracker::FlushDirty
Application::TickTimer
MainMessageLoop
WinMain
Which essentially says that the object which is being destroyed is being accessed later on.

Users should not call CreateAsset from calls which are destroying objects. We will enforce this rule in 2020.1, but for right now this is not something that they should be doing.