That’s…really stupid if you ask me. Sorry.
Even in the canon EU version of events between ANH and ESB, it’s clear that Vader understands exactly who Luke is once he learns his name, and adding the lines to the Emperor scene in ESB just muddle things and make the viewer have to do some mental gymnastics for the scene to work, where the original dialogue worked just fine for 34 years and there was literally zero reason to change any of the lines or add any new ones.
When they don’t even bother writing up some backstory in the new EU to make those new lines work, you know it’s clear to everyone involved that the new lines were a mistake.
a trolling bantha