Accidentally published fanfiction can be a tricky thing. Fanfiction often exists in a sort of gray area legally. When it's accidentally published, it could expose the writer to potential legal trouble if it goes against the terms of use of the original work. It also might lead to unwanted attention from other fans, either positive or negative. Sometimes, it can even start a big debate within the fan community about what should be allowed and what's over the line in terms of fan - created content.
Well, if we assume 'accidenrlt' is a typo and it should be 'accidentally', published fanfiction that's accidentally out there can cause all sorts of issues. For the original creators of the source material, they might not be happy if it violates any of their rights or if it's a really bad representation. For the fanfic writer, they might not have intended for it to be public yet or might have made mistakes in it that they wanted to fix first. It's a bit of a mess in the fanfiction world when this happens.