Are you only creating/playing the event once? If so, have you tried setting FMOD_ADVANCEDSETTINGS.randomSeed in your game when you create the sound system? Setting it to the system time should ensure you get correctly randomized playback.
Are you only creating/playing the event once? If so, have you tried setting FMOD_ADVANCEDSETTINGS.randomSeed in your game when you create the sound system? Setting it to the system time should ensure you get correctly randomized playback.