I have an app that is been tracked using git and the repository is hoted on github.
In my local computer the folders and files are these:
Git is case-sensitive, but Windows is not. So, the two directories aren't duplicates in Git's view.
If you renamed TulpepWebsite to TulpepWebSite sometime in the past, then all the files which were under TulpepWebsite would have been tracked by git under that old name, while any new files you added would be tracked under the new name.
To fix this, I'd just git-mv the folder to something else and git-mv it back to the old name. This will hopefully force all of the paths to use a consistent case.