I also have the same results. When clicking the "Files" icon in the launcher, it opens another instance with a question mark. If "Files" is selected from the dash, it will also open another instance with a question mark.
When attempting to lock the new instance with the question mark to my launcher, when clicking on the question mark it blinks, but "Files" never opens.
I also have the same results. When clicking the "Files" icon in the launcher, it opens another instance with a question mark. If "Files" is selected from the dash, it will also open another instance with a question mark.
When attempting to lock the new instance with the question mark to my launcher, when clicking on the question mark it blinks, but "Files" never opens.