

I just searched in there, like the new yorker: https://flipboard.com/@NewYorker and got the handle to follow the profile @NewYorker@flipboard.com, on the magazines I got the handle https://flipboard.com/@newyorker/cartoons-1hgpnrb6z and put the name (without the random alphanumeric) with the account like !cartoons-newyorker@flipboard.com.
I think this might be some heavy weight companies doing this, blocking their proxy nodes might be an option, or captchas to create posts, registrations, comments, etc.
They are automating sending these posts, like in the log on the screenshot, fortunately my instance is private.