I have some questions:

ROTJ:

3PO states in the opening that "Lando Calrissian and poor Chewbacca never returned from this awful place".

Wait a second. Chewie shows up with Leia. So what is 3PO talking about?

The Emperor arrives on the DS and tells Vader: "In time he will seek you out. And when he does you must bring him before me."

In the next scene with these two Palps tells Vader that Luke will come to him and Vader says: "He will come to me?".

Wait a minute. You were just told he would come to you in the arrival scene. What the heck is Vader talking about?