Hi,
I allowed myself to move this topic to the “Questions” category since I believe this is not an identified bug.
You would need to provide a PG for us to give you better advise and an example.
What I can say is that, in order to light your mug from above you need a light that casts light from above the mug towards the ground. You could also move your light with the camera.
In general, for product tour representations, I tend to use a 3-points light setup.
It uses 3 lights set in a triangle about 3-quarters top around the object and casting light in the center direction. This set-up generally makes for a good lighting of the object from all directions.
I hope this helps and as I said if you need better advise, please share a PG with us. We’ll be happy to help 
Meanwhile, have a great day 
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