Thank you for your question. In your example, everything works as expected: series attached to the left and right axis are independent and they are rendered from the same base point, therefore they overlapp each other.
You said that you expect that green bars should be placed side-by-side to other bars. To do that, just remove right axis and place all series at left axis - the chart will render in a way you need. Hope it will help.
Now I better understand your problem. Currently it’s impossible to achieve behavior that you need, but I think it’s important feature. So can you please create an issue on GitHub so we can investigate the problem and try to find a solution for it? Thanks!