I got the impression Chewie was struggling with the controls and was simply distracted for a moment.
I think it’s supposed to be that Chewie did it, but it has no effect because “We’re caught in a tractor beam and it’s pulling us in!”. But Harrisons delivery of the 2nd “Chewie lock in the auxiliary power.” sounds just like his first request, with no added urgency, so it sounds like they just used two different takes of the same line and it’s jarring.
JEDIT: I watched this scene last night, and Harrison’s delivery actually isn’t as bad as I remember.