Season two ends with Deja smashing up Randall's car, so it's possible that she continues lashing out and pushing away the Pearson family. Fans have speculated that when Randall goes to see an adult Tess in the future timeline, he is referring to either Rebecca or Beth when he tells Tess that it is time to see "her." The "her" in question, however, could definitely be Deja, and Randall is trying to mend the burned bridge. Perhaps Deja gets so out of control that she hurts someone in the family physically, and now she is in jail. Or perhaps it's not as sinister as that, but Tess has still chosen to cut her out of her life.