The kernel from https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2073047/comments/7 does seem to fix the problem. I've now repeated the process (waking from suspend + plugging in ethernet) two times without problems (I've also had to disable secure boot but that doesn't have an effect here, I guess)
The kernel from https:/ /bugs.launchpad .net/ubuntu/ +source/ linux/+ bug/2073047/ comments/ 7 does seem to fix the problem. I've now repeated the process (waking from suspend + plugging in ethernet) two times without problems (I've also had to disable secure boot but that doesn't have an effect here, I guess)