In case you are not already aware of the latest nfo syntax changes please have a look at
http://forum.kodi.tv/showthread.php?tid=292732
I thought first this is changed at Krypton but also Kodi 16.1 nfo files does already contain the <Name> tag at movie sets
Therefore it did not help to delete the tinyMediamanager database again and triggerd a re-import from the directories where the movie files and now Kodi 16.1 nfo files are located. The already viewed check box is correct imported from the nfo but no movie at the db has get one of the existing movie set entries of the nfo files.