It is a paradox...
If you put a subtle activation Beep when Lobot walks past them when his head flashes ... Then when chewie looks over his shoulder we hear the activation beep again but in the background this would help suggest what is going on. And chewie senses something is up because that lobot dude double backed.
It rams the the idea that he back tracked home.
As for Han and leia switching sides it's unfixable