I recall reading when the news first came out about this that she wrote it long, long before TKAM, and that she never liked it. It was her place of inspiration for the novel, but it was never meant to see the light of day. There was some debate about her ability to sign over power of attorney when she did as well. So to blame her, or Mockingbird, or her writing for this atrocity would be wrong if all those things are true. This is purely the wrong of money-hungry relatives and lawyers. But then, confusingly:

[...] but I'm suspicious: It reads much more like a failed sequel. There are lots of dead patches in Go Set a Watchman, pages where we get long explanations of, say, the fine points of the Methodist worship service.

I don't know what to think. I'm also reading further that there's another "found" book and I have to wonder if this is even more sinister. A fraud writing under her name that knows her, trying to milk it for all they can. And, seemingly, a racist. I cannot believe that Harper would ever choose to make Atticus into that.... disgrace that's described here.