I think you ran into this threaded here.
Thanks to reinob for pointing me into right remembering. I ran once into the same/similar and could not solve it So I thought of HW problems and defect of my beloved (now due to 'no telephony functions' gone) one. But it cured itself somehow, do not remember anymore how (really sorry ).
Did you try full power cycle (sometimes cures weird HW behaviour really!
Good luck (worst case scenario: reflash but ... )

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Or maybe have a look here (in case of adblock installed which gave me also headaches with CUP server administration site: 'add printer' )