Moving to a note flatted by key signature is spelled enharmonically
Using revision 2438, Toby Smithe's PPA
This is not a transposing issue as a composition of mine that I selected to start with two flats still had that bug affect it.
As you can see in the video, when I drag a note via the mouse or use the keyboard, notes in flat keys are enharmonically spelled. However, this works fine with sharped key signatures.