I tested https://bugzilla.opensuse.org/show_bug.cgi?id=1104571 on 2018.10.31
Tumbleweeed.
The same result as on Leap15. All RX and all TX packages are dropped
Connection is established, signal strength is good, IP is obtained, Routing is
set to default gw received from 4g modem, DNS servers are also received.
Cannot even ping gateway.

The same setup works as soon as I boot Ubuntu with no different settings in
NetworkManager.


wwan0: flags=4291<UP,BROADCAST,RUNNING,NOARP,MULTICAST>  mtu 1500
        inet 10.111.71.20  netmask 255.255.255.248  broadcast 10.111.71.23
        inet6 fe80::73fb:926a:b538:f135  prefixlen 64  scopeid 0x20<link>
        ether 7a:c6:53:8c:bf:03  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 1280  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 42  dropped 0 overruns 0  carrier 0  collisions 0