Same issue here--I just upgraded one of my nodes with a Realtek NIC to 8.03 and was bitten by this bug:
Jul 24 20:37:56 thinmox kernel: ------------[ cut here ]------------
Jul 24 20:37:56 thinmox kernel: NETDEV WATCHDOG: enp1s0 (r8169): transmit queue 0 timed out
Jul 24 20:37:56 thinmox kernel...