Hi Folk.
The problem of the solar disc in front of the clouds with Defer Atmo/Cloud on solves with Defer All Shading On.
I experimented with various attempts and put an image where the solar disc appears halfway between cloud and sky.
Even with Defere All Shading and Defer Atmo/Cloud
activated at the same time the problem is avoided.
I don't know in the animation but for the still images the problem is solved, even if the rendering time certainly grows.
Try and see.
Of course, you can always put Visible Disc Off and Stop with this issue.