It's not really noticeable to anybody else, I'm pretty sure, and it only happens ever now and again when I'm downshifting slowly, going through gears one by one on my way to a stop, for example. I'm thinking it has something to do with my 2012 knee surgery on my right side, the right leg is still not as good as the left. I'm probably doing something with my upper body to compensate and that moves the bike. Today I didn't feel it at all, now when I'm aware of it I'm already unconsciously doing something different to fix it.That's really peculiar. I have never had that issue at all.
Not sure how shifting would require counter weight....
I just thought it was kinda cool how little things make a huge difference on the bike, like a foot position.