To easily check if a `.gitignore` is responsible, simply do (with a *recent* version of git):

    git check-ignore -v -- path/to/ScriptableObjects/ 
    git check-ignore -v -- path/to/ScriptableObjects/aNewFile 

That will display the right `.gitignore` (or `.git/info/exclude`) with the rule excluding that folder and its content.

Typically, an ignored file can *still* be added with a *force* (`-f`):

    git add -f /path/to/ignored/file

In the OP's case:

    C:\Users\a\OneDrive\Documents\gitignore_global.txt

Check your [global config, as I mentioned before here][1].

----

The other possibility is that the folder and its files are part of a nested git repo, or a submodule.  
Look for:

- either a `.git` folder within your main repo
- or a `.gitmodules` file in your main repo.


  [1]: https://stackoverflow.com/a/29161554/6309