Interesting, I was just contemplating if it could be from a state actor wanting to see how the network will stop notes at the relay level.
Discussion
I have no proof whatsoever mind you but I have this "gut" feeling that I can't shake.
This reminds me of when something was spinning up thousands of npubs and following me and 7 other npubs. I would get like 55 followers every day. This went on for I think a couple of months and then just stopped and I haven't seen it happen since.