that is not the 'audiosnap' function in Sonar.
it's the latency compensation that Sonar and probably all other DAWS have.
you can record a track on track 2 (for example a guitar track) and that will not snap to your metronome automatically unless you enable 'audiosnap' on that track manually and set the snap etc....it's a complete other function from what you're seeing with your metronome track.
When your route 1 paticular track (your metronome track) out and then back into Sonar, that will automatically allign both.
it's not an error or bug, it's meant to do that and it's not called 'audiosnap'.
there might be a setting under Preferences that let's you disable that, I don't know.
at least, that's how I think it is...