Hi and welcome to the forum,
Please, do you have the latest EastWest instrument installed?
Can you see the meters on the Instrument Tracks? Can you see the meters on the Output Channels? Does it help if you try to increase the Audio Device’s Buffer Size? What Audio Device do you use?
What is the difference between the tracks where you get the sound and where you don’t get the sound?
Is it a problem with this instrument only? Do you have other instruments in the project? Do they play back?