Sounds like a case of brain burn-in. I had a similar experience when testing something and quickly switching from Arya to Auteur, which made the Auteur sound muddy because my brain was used to how the Arya sounded.
Were you using another pair of headphones before putting the Noire on? Ones you know very well?
Were you using another pair of headphones before putting the Noire on? Ones you know very well?