Source for Perfect Blue's camera negative being destroyed
The closest source that exist on the internet is hearsay, according to an internet user on a forum post on the topic of the Bluray:


  
    What's the source on this? I've never heard of this before.
  
  
  The disc compressionist, privately to me.
  - professorwho


All copies were sourced from telecine transfers (i.e. digital copies of the film), which is why you see certain artifacts and overall decreased quality.