I think it's a little bit of an illusion. My guess is that the die was tilted ever so slightly, so that one side of the coin received a slightly stronger strike and is more pronounced, while the other side received slightly less pressure leaving a slightly weaker strike on that side. Here, the left side of the reverse received the stronger strike, while the right side of the reverse received the weaker strike. Because the design on the left is in higher relief and more "bold," it gives an asymmetrical or leaning appearance. That is just my guess. I do not know whether or not this process would be possible if the reverse die was the anvil die, though.
If you think about it.. The Eagle is actually looking to the right Just imagine looking at it from behind