When Foundation Season 2 announced a 138-year time-jump, fans were most intrigued. Most of the story has already veered away from Isaac Asimov's books, with this angle advancing the war to come between the Cleon Empire and the Foundation rebels. Interestingly, showrunner David S. Goyer has quickly introduced a sinister caveat into Brother Day's reign on Trantor.
Source:https://www.cbr.com/foundation-season2-brother-day-empire-trouble/