It could have had to do with Infantino leaving Marvel (and returning to DC) the same year as this issue was drawn. I don’t know the whole story in detail, but I remember reading somewhere that he was never too happy working at Marvel. In one interview he refers to a lot of his work there as “mediocre”, though he did speak highly of his collaboration with Archie Goodwin.

He might have simply gotten tired of the jobs that Marvel was giving him at this point. Droid World can be a little bit sloppy at times compared to his SW work the previous couple of years, and the next issue (The Third Law) is simply plain lazy at times. The previous issue was also barely even recognizable as having been drawn by Infantino, implying that he mostly did layouts. Apart from the aliens (incl. Cody Sunn-Childe) it looks more like it was drawn by Tom Palmer, who’s just credited as the inker. So for whatever (specific) reason, it seems like a lot of artists at this time had to cover for him before he was eventually replaced by Walt Simonson / Tom Palmer as the main artist(s) working on SW.