Joined journal from boot until network is down and some more informations.could you (and others affected):
* share the journal from booting up the machine until the issue occurred
* try disabling some offloading functionality: `ethtool -K <nic> rx-gro-hw off lro off`
Then I reboot server and disabled offloading with your command on botn nic 2 and 3, but after 8 minutes network goes down again.