Hi
I entered a chord sequence C E F G into a song in song mode (also happens importing chords). pressing b 3 times gives A Db D E pressing again gives A C Db Eb. The A doesn't change and pressing # 4 times to get back to the original actually gives C# E F G.
Apologies if this has been mentioned before.
I'll check this when I work on the next update.
I just submitted version 4.0.9, which includes a fix for this:
http://www.arlomedia.com/apps/setlistmaker/support/release_notes.html