Had similar problems on all our Getac F110 tablets. If you are using ethernet and WiFi you can prioritize WiFi over ethernet.
The problem we had was using sim-card in tablet and using cellular connection from the tablet.
Smart sw engineers from Microsoft have decided that cellular connection will be disconnected if there is any other network connected to the machine, even if there is no access to the internet.
We had to make register modification to ignore all non routable networks and then remove the gateway from ethernet IPv4 settings.
Add new dword “IgnoreNonRoutableEthernet” to "HKEY_LOCAL_MACHINE\Software\Microsoft\Wcmsvc