With Tixati version 3.42 if I can view (in Peers section) a unconventional peer corresponding to :

Address = 192.xxx.xxx.xxx:xxxx (exact Local your gateway & port of Tixati running)
Country = Unknown
Source = Tracker
Status = Waiting to connect...

Does the usual operation or what network setting do you think can explain this ?

Do you have any trackers in your local network? Then it would be completely normal. You can always organise bittorrent file sharing in the local network that has no connection to the Internet. Check the trackers tab.

Not others trackers. That's what seems strange, isn't it ?