If you haven't seen the movie yet, don't read this.
Chewie returns to the Resistance base with Rey and injured Finn and as he steps off the Falcon, Leia is standing there, waiting, but they walk by each other.
"That was probably one of the mistakes I made in that," J.J. Abrams, co-writer and director of Star Wars: The Force Awakens told Slashfilm. "My thinking at the time was that Chewbacca, despite the pain he was feeling, was focused on trying to save Finn and getting him taken care of. So I tried to have Chewbacca go off with him and focus on Rey, and then have Rey find Leia and Leia find Rey."
So, Chewbacca was originally supposed to be clearly focused on getting Finn medical attention, but "because he was right there, passed by Leia, it felt almost like a slight, which was definitely not the intention."
JJ also talks about the speculation surrounding Leia and Rey and if they really knew each other before their hug.
"The idea [was] that both of them being strong with the Force and never having met, would [still] know about each other — that Leia would have been told about her beyond what we saw onscreen and Rey of course would have learned about Leia. And that reunion would be a meeting and a reunion all in one, and a sort of commiseration of their mutual loss," Abrams said.