I thought George’s beef was with the DGA and that didn’t happen until Empire was finished? The IMDB lists Kazanjian as an uncredited producer on ESB, but how much overlap was there between the end of Empire’s production and the beginning of pre-production on Raiders?
From what I’ve read about The Shining both ESB and Raiders were waiting for Kubrick to finish at Elstree so they could move into the soundstages. Howard would have been a very busy guy juggling two Lucasfilm productions at once.