Houston we have a problem!
Today I created a test user to try if my Twitter connector is working (fun thing, it is working on the second attempt to connect, on the first it was read only).
Now after the test was finished I deleted the user via the /remove me function, I entered the password and pressed the button there. Now the user is still shown in /admin/users and it can't be deleted by me (the admin).
However the user shows up in /admin/users/deleted and it says will be deleted. So it seems it is only a cosmetic thing. Also I have the option (trash can button) to delete other users.
I don't care in that particular case, but it seems something there is b0rken.
This is how it looks:
Never mind the red arrow.