As the THX-release was only released on Video and LD, and being years before 16:9-TVs, I guess the misplacement of the intro-text wasn't this obvious on 4:3 screens.
The quality of the THX-crawl is really horrible... the perspective of the text isn't right, compared to the perspective of the complete crawl, and there's still a typo ("nach Haus" instead of "nach Hause" as in the SE-crawl). Also, the crawl has been created interlaced, since those versions were only released on TV-media (VHS and LD), and progressive TV-sets or beamers didn't exist back then.
Coming to "Das Imperium schlägt zurück" and "Die Rückkehr der Jedi-Ritter", their THX-crawls look just as crappy as the ANH one:
The SE titles though show something interesting... here are all three:
ANH
TESB
ROTJ
Obviously the title-cards for both "Imperium" and "Jedi" weren't created with as much care as the one for ANH (and it looks like the same one has been used for TESB and ROTJ, with just some color variation). The same applies to the crawls:
Though this time the chapter name "Das Imperium schlägt zurück" isn't mispelled as in the original crawl from 1980 as "züruck", it says "Tattuin" instead of "Tatooine" in the "Jedi"-crawl, though I am not sure how it was spelled in the 1983 crawl.