Intermittent Host Sign In Message

I have two (2) systems at two (2) different locations, which are defined in my "Computers & Contacts", running TeamViewer Host; which randomly issues a message to me: "??? has signed in" where "???" is the ID I have assigned to the system. Both systems have other systems at their respective locations, also running TeamViewer Host which do not exhibit this behaviour. Any Ideas?? Thanx ;r