[dr_daw]

I think you may have found the culprit, but again; when you're not zoomed in very close then it's hard to definitely say. The key is to check at almost the 'sample' level and check to see if one waveform is going up while the other is going down or vice versa. At the end of the day if it's parallel processing it'll matter, but if it's not, then it doesn't matter because the original would be muted/disabled.

If in fact 'Air Kill' is inverting the phase, then that would be a good thing to know for parallel processing. I would have a tendency to think you have found the culprit; but a zoomed in waveform would be better.