If you're using the Musical Typing feature to play notes in GarageBand 2, please note that the Pitchbend buttons on the Musical Typing keyboard (and their corresponding keys on your Mac keyboard) will not work when you play certain note combinations. This is a known issue.
If you play a C note (by pressing the A key on your Mac keyboard) along with any other "white key" note—D, E, F, G, A, or B—the Pitchbend down button (the 1 key on your Mac keyboard) will not work. If you play a D note (by pressing the S key) with any other "white key" note, the Pitchbend up button (the 2 key on your Mac keyboard) will not work.
If you play a C and D note together (by pressing both the A and S keys), then neither Pitchbend button will work. All other note combinations work as expected. If you need to apply pitchbend to a chord that uses an affected combination of notes, you can add it after you record the chord from the Musical Typing keyboard, using the editor.
This document will be updated as more information becomes available.