Translating between Bokmål and Nynorsk Norwegian, I note that issues fixed in the MT source code and working at do not work in the Content Translation interface. This suggests that Apertium has not been updated in a while. I do not know where to look for the date stamp, but I ''hereby ask for an update'': The issues we have fixed were very frequent errors, and the MT tool is now much better than this interface is able to show.
Topic on Talk:Content translation
Thanks for heads up. I'll look into new release and update it. We are at 0.9.0~r69513-1 version and need to update 1.0.0.
Tracker task is: https://phabricator.wikimedia.org/T218184 (will update description too).