Goof: The trolls are out and about in the day time and not turned into stone.
Female gnomes only give birth once in their life, and it's always twins.
This is the first time we see David use his animal hypnosis powers
Goof: David stated in the first episode that he'd never actually seen any other mystical creatures (wizards, elves, etc.) before. So then how does he know the Elf King?
Goof: Despite clearly being daytime, Holler and Pat are neither turned into stone or concerned.
Goof: When the gnomes attack the trolls in the snow field, an unnamed 5th troll is inexplicably with the group.
This is the first time we see a troll turned into stone upon touching sunlight.
The different types of gnomes, according to David:
Dune Gnomes (sand/desert dwellers)
Siberian Gnomes (snow dwellers)