Well, May is the SW anniversary...I don't remember if they were doing any special offers or anything. It was maybe when Mace came out. Other people will remember better. I think I came back from my four month break around June or July.
It's part of the reason why I'd like to see multi-year data...is there always a spike around this time, perhaps as kids get out of school? But I definitely think the rapid decline immediately after is just expected attrition of new players.
It's also hard to tell just from aggregate data how many accounts are alts and what the behavior is like for people dropping engagement on those.