Hi,
It is indeed the pitch bend that is giving you grief
The good news is that Composer allows you to edit that pitch bend using the Graph Over Notes tools. It's a MIDI cc editor that you can edit right over top of the notation, so you can see exactly where it's going to affect the sound.
In Graph Over Notes tab, click on the Pitch Bend button (quarter note with a wavy line) and you can see AND edit the Pitch Bend(s) that are in the score. If you want to just delete all of them, (1) click the Staff Select button, then (2) hit the "Delete" key on your keyboard.
To edit them, you can click on whichever draw tool you want to use (depending on how you want the bend to sound). This will probably require a little practice if you've never done it before, and Zooming in the score will help with "fine tuning" it (gives you a bigger "canvas" as it were.)
Hope this helps get you going. David Jacklin is the best guy for Pitch Bends that I know - he may have more/better tips.
ttfn,
Sherry