Sun Rise Under the Clouds from a Cessna

Sun Rise Under The Clouds:
In flight Cessna Citation VII flying at FL 280

FL 280 means Flight Level at 28,000 feet altitude with standard pressure. Aircraft model is Cessna Citation VII.

This video clearly shows the existence of a local Sun over the Flat Earth plane, but at the same time it intrigue me a lot.

The Sun is apparently below the clouds lighting them up and the airplane is flying above the clouds!? Is it an optical illusion or a fact?

Local sun