When Mayor Humdinger first goes to the university to take the Cloud Catcher, the roof opens so that it can fly out. Despite being in the middle of a torrential downpour, no rain comes in through the massive hole in the roof. Moments later, once the Cloud Catcher has done its job, the Mayor stands and basks in the sunlight now streaming through the same hole.
Two different cars (the green one Ryder gets stuck behind while en route to Humdinger's fireworks display, and the yellow one in the river near the end of the movie) have the exact same license plate number: 708 924.
If you go to the Spin Master Entertainment logo on here, if you look at Marshall, there is an animation error on his pup tag and collar.
When Ryder and the Paw Patrol pups are heading to Adventure City, there's no appearance by Robodog to drive the Paw Patroller, instead it's Ryder driving the vehicle. Considering Liberty's vehicle number is 22, the means this movie is supposedly taking place in the current season which means Robodog should be present, and no explanation was given as to why he wasn't there.
During the origin story recap for Chase, we see a flashback scene of when Ryder rescued Chase. In that scene, Ryder is clearly several years younger. In the subsequent years, Ryder matures, starts Paw Patrol, earns a fortune by starting a merchandise business, branches out in to a new city where his Avengers-style personal skyscraper is built. Yet, Chase hasn't aged a day despite the puppy stage of a dogs life only lasting about a year.