The cropped screen grab below (Screen Grab.jpg) shows the key changing in measure 33 from F Minor to Bb Major. The Alto part properly shows the cancelling natural signs for the dropped Ab and Eb, but the Soprano part does not show the cancelling natural signs for the dropped Ab and Db, even though it correctly shows the Bb Major key signature.
I have tried this in Composer 3.0.6 and get the same results, so I'm reporting it here.
Here is a link to my posting of the full score, as the upload process won't let me upload the score again, by any name:
http://www.notation.com/vb-forum/showthread.php?t=34257
Ralph Rayner