The nynorsk-bokmål pair in Apertium does not work, or is not posted properly. This used to work.
This language pair is the primary reason why the communities want to try out this extension, and it would be really nice if it could be reenabled. Bokmål and Nynorsk are the two official written variants of Norwegian, and nowiki and nnwiki are the two Wikipedia projects using those two variants.
During the test I was editing from nowiki (Bokmål).