Tonights work rebooting machines into a new kernel, 4.15.0-20.21, to fix an issue with the Ethernet controller wedging went cleanly and initial indications suggest that it was a success. The real test will come later this afternoon and evening with heavier traffic but so far so good.
Well not 100% success. It reduced the occurrences from several times an hour to around once a day. An improvement to be sure but not a complete fix.