What about detrimental mutations? Evolution accounts for them nicely, but does not claim they are not dysfunctional. Methinks you made that up by yourself.
The notion of dsyfunction is related to the ideas of design or purpose. I can say that my refrigerator works as it is ought to because it was designed for a purpose. Presumably there is no corresponding purpose in any evolutionary process. A 'detrimental' mutation is just as much a part of the evolutionary process as a 'beneficial' mutation. A dead organism killed by some mutation is part of the same evolutionary process as a living organism across the street that was not killed by the mutation. Both can be said to function 'normally' in the random, impersonal evolutionary scheme. As far as I can tell, the only 'purpose' of evolution is total extinction.
Cordially,