I tried to read the article a bit more carefully. It appears they are largely just selling off the stake they bought back from Vivendi in 2013. Most likely recouping the huge amount they had to go into debt then.
Also, executives selling large amounts of stock when their stock is at a high water mark is nothing new and does not necessarily indicate anything nefarious. See Jeff Bezos selling 1.4 billion USD in shares of AMZN this year alone.