I asked this as a poll on a message board that since deleted many of the comments sections. This mainly applies to superhero comics.
Every now and then, two books that are published at roughly the same time that contradict one another. One example was with an issue of Amazing Spider-Man, which featured details that contradicted the first issue of Jonathan Hickman’s FF, in which Spider-Man joined the team. It’s also been argued recently that Peter’s conversation with God in Sacasa’s last issue of Sensational Spider-Man should have figured into One More Day, which was published afterwards but written much earlier.
When these types of things happen, who is to blame? There are several potential individuals to blame. The easy answer is the editors, but there are often other factors. In my options, I’m including the editors, as well as the writer and artist, as part of the creative team.
The creative team of the book that was written last.
Often these contradictions result from projects that are written months apart. One could argue that it’s the duty of the later writer and the editor to make sure that what they’re doing doesn’t contradict work that has already been commissioned.
The creative team of the book that was published last.
The fans wouldn’t usually know the order in which books were written. But they know the order in which books were published. And it’s easy to blame the creative team of the book that was published last, under the argument that they should have had more time to fix the error.
The creative team of the book that is less important.
If something that happens in a generic Spider-Man mini-series might contradict something that happens in Secret Empire, it’s the responsibility of the creative team of the mini-series to make sure that it all makes sense, because theirs is the less important book.
The creative team that has lower name recognition.
If Grant Morrison and John Romita Jr. are working together on a Batman story and it contradicts what’s going on in Batgirl by Hope Larson and Elearnor Carlini, it’s Larson and her editors’s responsibility to make everything work, because Morrison and Romita Jr are the better-regarded creators, and their time is therefore more valuable.
The creative team that takes less time per page
Some writers are more prolific than other writers, and some artists are more prolific than other artists. Therefore, if there’s a contradiction the more prolific creative team should figure out ways to resolve the issue, as a patch would take them less time.
The creative team of the book that is lower in quality
One possible way to assess blame in the event of a contradiction is to decide that it should go to the creative team of the book that is of a lower quality. This book won’t be remembered as fondly anyway, if at all. It’s possible that in the long run, more readers will experience the better title’s version of events first, and they’ll be distracted by the contradiction should they ever read the weaker title.
Personally, I think it comes down to the order in which the books were written.
The writers should have access to scripts for related projects. So it shouldn’t be too difficult to make sure that your work ties into something that’s been already commissioned, and which an artist is probably already working on.
If this is not the case, whoever is preventing a writer from accessing already commissioned scripts is at fault.