I’ve had a long going issue with shadows and animating the World colours, an issue in both standard BGE and UPBGE. When there are no shadows in the scene or shadows are disabled, the World colours can be animated, but it does not work when there is a shadow in the scene.
My work-around in normal BGE was to remove the light with the shadows, animate the World colour and then bring the light back in. It’s not an ideal solution for longer animations, but it’s something.
For UPBGE there isn’t a solution just yet. I’m not sure if shadows can be disabled and then re-enabled, but if they can, I’m not sure if the World animation would even work.
Has anyone else come across this issue?