Actually, I just did some more probing and I realized that even if forcing my Master Bus to 7.1, having the Project Platform set to Desktop 5.1 caused this to happen. When setting to Desktop 7.1, panning worked as normal. But the behavior is still curious, especially when it was pushing a substantial amount of audio to channel 6 which was toward the opposite side of the pan. I am assuming that this was because the combination of the platform setting and the master bus setting was outside of intended use (i.e. incorrect). I also assume that if I’m mixing in 7.1 (and platform set to 7.1) but the user is in 5.1, the mixdown would be more expected than what I was experiencing.