The rumor is that J.J. Abrams rewrote the Star Wars 9 story, incorporating new scenes between Lando and Chewbacca.
Before these rewrites, Joonas Suotamo had apparently already shot most of his scenes as Chewbacca during the production of Solo. Apparently, Chewbacca wasn’t supposed to be in Star Wars 9 much.
And it’s not revealed if Ron Howard was behind these, as J.J. Abrams was deep into pre-production on Star Wars 9 at the time.
It’s speculated that Williams hadn’t actually signed onto Star Wars 9 until late June, and he wasn’t in the script that J.J. Abrams had already in place to shoot.