That's been happening a bit recently.

https://news.ycombinator.com/item?id=11837687

(I think there are others, but I can't find them now.)

Both usernames end in 2

Yeah, but I still wonder how often people copy comments around like that. It's not like that was some great writing or anything, but it was copied word for word.

Maybe it was some bot, but that's an odd bot.

I've seen it happen on YouTube (not to me); highly upvoted comments get copy/pasted a month or two later to "steal" upvotes for someone else.

It could be a bot tactic to build accounts with karma that can later be used for astroturfing, using proven comments from elsewhere. Maybe governments and organized astroturfers have automated that sort of thing more than we think.

Nail, meet hammer.

Hopefully in this case the nail is comment plagiarism and the hammer is more careful pattern matching in moderation systems.