I was rendering a shot with a glowing object and I noticed that Screen based AO causes a 'banding' in the glow/ halow/ orb is present at the end of the last render pass.
I wonder if this has to do with a setting or just a casualty of using screen based AO.... The glow is looking great until that last pass finishes and the AO is added in.
I'm in V18.
I increased the multipasses but that didn't help. Both with and without motion blurr carries the same results.