I think your problem results from quantizing after you have applied pitch bend. Pitch bend adds many note messages to the track in very short lengths to simulate the pitch sliding up or down. If you then quantize that track, all these very short micro step notes get shifted to the closest 8th, 16th, etc., note. You may also notice that the beat that these notes were moved to by quantizing may have a weird thump or added noise resulting from all the short notes in your pitch bend being played at once.
1. Don't use quantize on tracks with pitch bend.
2. Record the track without using the pitch bender, then quantize, then (if your squencer allows it) add the pitch bend to the desired notes in that track during a second record overdub pass.
Hope this helps.