LOL, maybe so, everything I'm reading is citing his dislike of the script and IMDB has him quoted saying:
[Guinness discussing how much he disliked working on Star Wars (1977) and his attempts to encourage George Lucas to kill off Obi-Wan Kenobi] "And he agreed with me. What I didn't tell him was that I just couldn't go on speaking those bloody awful, banal lines. I'd had enough of the mumbo jumbo."
Apparently Guinness really hated to lines.