Multitrack pitchbend

I'm having some trouble importing midi files into garageband. I'll drag the desired file into the garageband window. This creates separate tracks for each channel of the midi file, 15 in all. Now, all of these channels have pitch bend changes associated with them. However, these changes only appear on the first track of the sequence. Any idea why this might be? If I record the same sequence into garageband, squashing all channels onto one track, every channel's pitch bend changes appear as desired. However, when importing I'm left with only the first channel's worth of pitch bend data, or at least only that visible in the note editor. Thanks in advance for any help.