The 'Login on a new device' security notification alerts you when your DuoxMe account has been logged into on a new device. It also indicates the type of device used to log in: iOS, Android or Web.
Logins via the web are linked to the connection between your DuoxMe account and virtual assistants such as Alexa or Google Assistant. If you use any of these assistants, the notification may reappear from time to time. This is because the service automatically renews the login credentials needed to maintain the connection between the virtual assistant and your DuoxMe account.