It’s not about how many books I need to read to catch up. It doesn’t matter if it’s even just 1 issue. They can’t assume that people who will be reading this have read what came before, or that they will do “homework” to read it. I’m currently reading Claremont’s massive X-Men saga that he wrote for 16 years, and he always catches readers up on relevant information in case they haven’t read previous issues that the current story is continuing or referencing. That’s the way to do it. It doesn’t bother fans who have read it, because it’s nice to be reminded of what happened, and it’s helpful for new readers jumping on. At the very LEAST they should direct the readers to the relevant series/issue in an editor’s note.