I’ve noticed a lot today.
They do have a certain MO. They will post very short messages but lots of them on a thread, one after another. They are often banned quite quickly but re register and return to the thread as if they are a new user. So an OP can feel as if several people are being disagreeable and unpleasant when it’s actually the same one. I think they’ve used five usernames today alone and they are the ones I’ve counted.
Probably a slightly obvious question but can’t this be addressed, through limiting registrations or something?