Steps to reproduce :

- create a folder named Test
- create a new scene
- try to save the new scene with the name Test
- notice that when trying to save the scene it will open the Test folder, suggesting that you should save it here instead of saving it in the Assets root folder

Won't fix this since this is how other apps work on Windows as well. If you're trying to save some file with the same name as an existing folder, that folder will be automatically open. The workaround in the case of this specific bug report is to save the scene as test.unity specifically. That will save the scene in the Assets folder