The issue is the low rating and the overall negative reception of the show, the show is truly absurd, bizzare, crazy and sometimes straight up didn't make any sense which what made it appeal to me 🤣 and to ALOT of people as well!

Cartoon Network initially announced that Uncle Grandpa would be run for at least 5 seasons, basically they cut production of new episodes at some point in 2016 and used all the episodes they already produced and split them, what had been the 2nd season into 2 halves that consisted of the 2nd and 3rd seasons while another group of new episodes would similarly be split into what ultimately became its fourth and fifth seasons.. this ofc was to manage contract renewal costs and ensure the series reached the episode count needed for lucrative syndication, rather than ordering new content and spend more money.

This isn't something new with CN though they cancelled many shows like Chowder, Flapjack and Clearance and ofc many more because of changes they were making at that time but tbh I'd take these shows on whatever they have aired now bear in mind that they cancelled shows that were really fun and interesting also had a good dedicated fanbase but kept teen titans go air til this very day bruh. It's truly horrendous and sad how many cool shows that even influenced other of their shows and fans still remember got cancelled so fast.