MIDI Track Problem

Fairly new to working with MIDI tracks.  Panned a MIDI track hard left and it changed the synth sound in SynthMaster.  Can't get the original synth sound back even if I re-add SynthMaster and copy MIDI clips to new track.  I can leave it panned hard left and it sort of sounds like it should, but set in the middle it now sounds different.  Any ideas would be appreciated.