We have seen a recent wave of impersonation accounts which claim to be another fediverse user, often with a similar username and boosting some posts from the original account, before reaching out to followers over private mentions and claiming to have issues with their original account.

Please report them if you see them!

@staff here is one: @gubi_ thanks for asking, I was going to report it but the account didn’t post anything until now, so I was waiting for a more solid ground for my report. But now I understand that the problematic activity is done under the radar.
@staff btw, looks like I can’t report an account with no public toots, maybe this is something worth a feature request…
@staff I saw also @gubi - zero post, joined in April 2023, up to you to check for suspicious activity under the radar.
@gubi @staff @gubi it's ok 'm not a bot.
I use mastodon rarely

@gubi @staff
I was able to report this account using the Tusky app.

(I didn't actually send the report, but I was able to complete the process up to then).

To be clear, I didn't send the report because I saw no reason to. There is nothing wrong with having the same username on more than one Fedi server.