I spent at least an hour Tuesday night and took nearly 200 photos just focusing, unfocusing, refocusing, testing, moving, retesting the Nokton 50mm f1.1. I wanted to be absolutely sure that it was the lens with the problem, not my usage of it or my M8.
Even at f2.8, there was noticeable backfocus while my 90mm Elmarit f2.8 was spot on. However, by the end of the evening, I was pretty adept at focusing and then unfocusing just enough to get a good photo.
The amount of backfocus changes gradually from 1m to infinity, so with near-focus objects I have to make quite the correction by turning the focus ring several degrees clockwise. It takes less and less correction as the objects get further away. Past 25 feet or so and I can just focus normally.
However, all the practice paid off yesterday because I managed to pull off most of the shots.
Today the lens gets shipped off to DAG in Wisconsin for adjustment. Let's hope they can make it as good as new.