Just had the same problem...this might help some others. Select your midi notes that you want to crescendo within your mIdi region in the PIANO ROLL...click on midi transform, select crescendo, and in the bottom left hand corner of the midi transform crescendo screen go to settings (wheel cog with a down arrow) and select "absolute position" I think by default "relative position" is selected and is causing the problem. Now make sure in the position parameter you put the beginning position and the end position that your selected notes fall into...you can then select your range of velocity to crescendo and click "operate only" done.