Steps to reproduce:
1. Open project from Case 1300104
2. Open any scene inside the project
3. Open another (different) scene
4. Go to File > Open Recent Scene
5. Pick an entry different from the currently open scene

Actual result: The  scene doesn't open.
Expected result: The scene opens or it shouldn't be added to the "Open Recent Scene" menu.

Note: this issue only appears when upgrading a project from any earlier version to 2021.2.0a5 or above. The Recent Scene functionality was changed to store scene entries by GUID rather than by a string path inside the EditorUserSettings and that fails to upgrade properly.

Workaround: delete all entries related to RecentlyUsedScenePath from YourProject/UserSettings/EditorUserSettings.asset after upgrading to 2021.2.0a5 or later. This way there will be no dangling string entries that break the Open Recent Scene menu.