When Victoria Vance enters the jail cell, the top bunk to her side is clearly empty. When she turns back inside after yelling at the guard, Mayor Humdinger appears learning over from the top bunk, was previously empty.
Despite there being 7 crystals, at the end Skye only has 6 on her pup tag.
Near the beginning of the movie both the Paw Patrol and the citizens of Adventure City are watching the night sky for the meteor shower, but no one notices the tractor beam from Victoria's machine. It seems hard to believe that something that bright would go completely unnoticed.
For some reason Victoria Vance, a "mad" scientist who manages to construct a "meteor magnet" out of scrap materials, had to steal an electromagnet which is one of the easiest devices for even a bad scientist to make.
No mention is ever made of why Liberty didn't have a "mighty" vehicle when the are first introduced, yes she has a vehicle later.