Darth Cadavra said:
...it's never made sense to me that Vader or Palpatine would consider Luke a "new" enemy several years after he saved Leia and destroyed the Death Star......
I think Palps sees him as a new enemy because Luke has just made contact with Yoda.....there is a tremor in the force......'I have felt it' Vader says.....the force is like a spiders web with Palps in the middle.
J