Editor throws NullReferenceException while setting AppID or uploading access token in Facebook Player Setting

Steps to reproduce:
1. Create a new project
2. File > Build Settings > Facebook
3. Player Settings > Publishing Settings > App ID or Upload access token
4. Enter App ID or Access token

Actual Result:
Observe NullReferenceException while typing App ID or Access token

Reproducible on:
2018.3.0a5, 2018.3.0a1

Working fine on:
2018.2.0f2, 2018.1.0f2

Environment :
Windows 10
Unable to check on MacOS due to BugID 1046782 - Facebook platform support is not detected by the editor on MacOS

Error Details
NullReferenceException: Object reference not set to an instance of an object
UnityEditor.Facebook.FacebookSettingsExtension.PersistChanges () (at C:/buildslave/unity/build/PlatformDependent/Facebook/Extensions/Managed/FacebookSettingsExtension.cs:37)
UnityEditor.Facebook.FacebookSettingsExtension.PublishSectionGUI (System.Single h, System.Single kLabelFloatMinW, System.Single kLabelFloatMaxW) (at C:/buildslave/unity/build/PlatformDependent/Facebook/Extensions/Managed/FacebookSettingsExtension.cs:252)
UnityEditor.PlayerSettingsEditor.PublishSectionGUI (UnityEditor.BuildTargetGroup targetGroup, UnityEditor.Modules.ISettingEditorExtension settingsExtension, System.Int32 sectionIndex) (at C:/buildslave/unity/build/Editor/Mono/Inspector/PlayerSettingsEditor/PlayerSettingsEditor.cs:2548)
UnityEditor.PlayerSettingsEditor.OnInspectorGUI () (at C:/buildslave/unity/build/Editor/Mono/Inspector/PlayerSettingsEditor/PlayerSettingsEditor.cs:580)
UnityEditor.InspectorWindow.DoOnInspectorGUI (System.Boolean rebuildOptimizedGUIBlock, UnityEditor.Editor editor, System.Boolean wasVisible, UnityEngine.Rect& contentRect) (at C:/buildslave/unity/build/Editor/Mono/Inspector/InspectorWindow.cs:1531)
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr)