I just posted a workaround solution to this somewhere else when a friend asked the same question.
I realised a couple/few years ago that you can use a cloud, instead of atmosphere haze, the TG lightsources and atmosphere nodes have never played well with each other so I tried to find a way around it. I would have thought it could have been properly fixed by now but maybe it's a bigger job than we imagine. It is a pretty major problem, though, in my book.
See the difference in this image, atmo(32 samples) and lightsource on the left.
Cloud(9 samples) and lightsource on the right.
A real pain when you consider how important both atmosphere and light nodes are in 3D rendering, but it works, at least.