In the auditions, Flim-Flam's fingers transform from four to five.
In the past when Mumsy held baby Scooby, his fur color was normal brown. But in the next scene it was the same shade of brown as Scrappy's.
After Time Slime set the Dial to the Future, it changed from the Future to the Present.
Vincent's boots change from black to purple.
In the future, Daphne and Shaggy (and even Bogel and Weerd, who should not age) look significantly older, whereas Flim-Flam and Scrappy do not appear to have aged at all.
In the present, Mumsy and Dada-Doo appear as fairly young. In their other appearances in this and related series, they are in their senior years.