Mainstage Help

My Mainstage concert has some samples in it, but when I go to play the samples the original note that the sample is assigned too plays. (for example I have a vocal sample attached to c6 and when my keyboard player hits c6 we will hear the note c6 prior to the vocal sample). I cannot figure out a way to get rid of it, I've gone through all the settings, the sampler, and watched tons of youtube videos. I am at the point where I want to uninstall the mainstage audio files and reinstall them but I dont have access to those files as we got this whole file from a third party. Is there a way to fix this? Please help.