Routing to Google Map services issue

I’m developing an Android application on a tablet that must use both Ethernet (trough USB adapter) and internal LTE carrier (or WiFi) to access Google Map services.
When I connect the USB/Ethernet adapter the application becomes unable to authenticate on Google Map services and therefore map is not populated at all, when USB is unplugged the application works correctly and Google Map component correctly shows its content up to the maximum level of detail.

May this depend on a routing issue? How can I fix this?

BTW the Ethernet port on this device is used only to access other devices located on a private LAN whose network is known.

PS The device is a Samsung Galaxy Tab S2 8.0 t719 running Android 7.0.

— UPDATE —

I’m not certain of the missing authentication since USB port is busy and I cannot see app logcat dump in realtime but the behaviour is the same I can observe if Google Map authentication fails for some other reason (i.e. WiFi turned off while debugging, invalid Google Map API key etc).