"Your account has been accessed from another location..."
Got it, went on these forums (logged in fine), waited like 2 mins and it didn't happen again.
I have 2-step authenticator active, and don't have other devices. Since I don't know if this is a Uplay problem or there's a reason for a hacker to enter my account then leave again, I'm posting here because I'd really rather not be held liable for any bannable offenses the hacker may use