Yes, it seems there is a little issue about rules that are not accepted by some people who flag pictures because they are nude filters (post #2281363 and post #2301928). There is also one message that one approver "believe" (lol) it breaks the rules.
But if one reads the term of service page (where rules are listed) one change says explicitely that nude filter images are allowed on Danbooru:
"2.89.0: You can now upload watermarked, poorly compressed, and nude filter images, but they are discouraged and the original uncompressed artwork is preferred."
And I don't know why the other thread 7 years (forum #16472) ago was closed but I think a seperate thread would be good.
I've had a little talk with two moderators yet and I had two proposition how two understand this rule (2 varioations that I just copy and paste):
1. One can upload nude filter images with no restraints unless it's bad quality and even when the original pic is on dabooru, it doesn't matter
2. One can upload nude filter images with no restraints unless it's bad quality or the original pic gets uploaded.
What's the case?
[...]if this rule has some importance (variation 1), then the flag reason should get nuked.
(And it seems both moderators tend to variation 1)
Since this post got flagged by someone with approval powers I feel there is a big distrust in existing rules.
Updated