Weird sound on bassline playback

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I keep getting this weird sound when I playback my tunes on logic on the wobble basslines, I use massive to make them but it seems to be fine when I play them on the keyboard, which makes me think it is probably something to do with logic because it only happens when I playback the whole tune. Does anyone know what could be causing this, please help! its getting so frustrating.

Here's an example of the sound http://www.filebox.com/c9tfxktzffj8

when i play the sound on the keyboard its just a smooth kind of wobbley sound.

Thanks for any replies