Okay... I have been using perchance for like 6 months or so, looked at many different generators, and have never seen this happen. So, I don't know how I've managed to dodge that all this time, but you get it every single time. Very unusual...
I get this behavior as well... but for me it is on my "personal" gallery that i made with a long convoluted name to prevent anybody form using the same name... so basically just another form of this "public gallery" you talk about. any image in here marked as NSFW will always be blurred, no matter how many time i tick the box to undo this. Maybe a browser issue? i am on "Edge".