I reproduced your setup and see the same thing. It seems that the hierarchical List data type (which a File path Type is) will automatically coalesce letters that appear similar such as O and Ø, even though they display as separate categories. This seems a bug to me.
Since your folders already contain the letter groupings you want, you could based the column on it:
left(removeleft([Filename (path)],12),1)
and then have another column show your folder tree beneath that:
removeleft([Filename (path)], 14)&datatype=[list]
Of course,you'll need to special case your Compilations or other exceptional folders.