As an experiment, try changing the Pitchbend range on the keyboard itself, one at a time, and then check BiaB's response to each setting.
See if perhaps one of the other settings works.
--Mac
I tried changing the keyboard bend all the way to +-1 octave (+-12 semitones), while testing, I moved the wheel slowly down on middle C, while recording on the melody track, as soon as the notes started to bend the bend immediately springs back to C, no matter how far the note is bent up or down, if the wheel is moved a little faster, the bend actually sounds arpeggio like, and not a smooth bend, but when not recording, and previewing on the Thru channel, the bend is very smooth.
Default recording is on the melody track, but using Thru to listen while recording.