I think I have gotton this before as well (can't remember when).

>Today I received two emails from accounts.google.com regarding two of my email accounts, indicating that a suspicious sign in was prevented. The emails indicated that the attempt was made from a certain IP and the address in Florida. At the time when this happened, I was connected via VPN to a customer network in Florida. And I had my Outlook open, which connects every so many minutes to check for new emails. Is it possible that since I was VPNed to a server in Florida, Google "saw" my Outlook connections as if there were done from a different than my IP and from a different physical location?