That is the sample (or group of samples, actually) that are assigned to play with a velocity of 29 or lower.
Quick fix: go to functions>transform>velocity limiter. In the transformer window where it says "max" change to "min" and change value to 30. Hit 'select and operate"
You could also edit the instrument itself, but that's too involved to explain here. Consult the manual and start poking around.