To be honest, I can't remember the exact books that had their tags duplicated, one was an Agatha novel but that's all I can remember there.
What I'm doing now is going through all of the books I added in yesterday. I've deleted all of the tags and have done a Ctrl+D on them as a batch. It's just gathering results now but this is pretty much what I did to get the incorrect tags so if this works, then I've got no idea how to recreate the problem
