After helping out with the script to Star Wars: The Force Awakens, Kasdan apparently only agreed to write Solo: A Star Wars Story if he could do it with his son Jonathan.
In a recent appearance at the Austin Film Festival (via SyFy), the writer of Star Wars: The Empire Strikes Back appeared to claim that his final entry in the galaxy, far, far away faltered because of problems at the studio level.
It seems the father and son writers had no issues with the film, but Lawrence Kasdan said that after the script left their hands, problems ensued.