Certain wind instruments in the Garritan libraries (such as the Garritan Instruments for Finale and Garritan Jazz and Big Band 3) can sound cut-off during swing playback. You can fix this behavior by deselecting Enhanced Jazz Feel Using Automatic Tonguing in your Human Playback Preferences (MIDI/Audio > Human Playback > Human Playback Preferences...). Turning_Off_Enhanced_Tonguing_in_Human_Playback_Preferences.png

This is limited to the Garritan Instruments for Finale so you can also select the SmartMusic SoftSynth instruments under the Device column of your ScoreManager (Window > ScoreManager) for better performance as well. Selecting_SmartMusic_SoftSynths_in_the_ScoreManager.png 

Please contact Customer Support and send us your file by clicking Submit a request above if you're still having trouble with your playback.