Comment by fma

Yep I got 2 on Jan 9th. he e-mails come from security@mail.instagram.com

I also get a bunch of these e-mails from them every few weeks:

Sorry to hear you’re having trouble logging into Instagram. We got a message that you forgot your password. If this was you, you can get right back into your account or reset your password now.

So, I guess you can actually message them, pretend to another user to rese password? I don't follow many people or have many followers. I can't imagine the attempts on other higher valued accounts...