Factual error: The episode has Mona Lisa and Teddy traveling to Yakima, Washington, showing green, tree covered hills. Yakima is in the middle of the Washington State desert, so the topography would be mostly flat, desert terrain, with yellow and brown colors.
Suggested correction: Don't think you have ever been to Yakima because Yakima is surrounded by hills and the only part that is flat is in the valley and Terrace Heights. I live in Yakima, and the map they showed of E Yakima Ave and Chestnut Ave and filming is wrong, though, because that area of the map is mostly neighborhoods, small businesses, and mini-marts. No trailer parks with a bridge nearby that has hills behind it in that area.
Factual error: When they go to 1954, the hamburger drive in says it has frappes. Not invented till '57, and not in the US public eye until at least 45 years later.
Suggested correction: What you're describing is a Greek café frappé made with instant coffee. In New England "Frappe" is what many would consider a milkshake with ice cream in it, and has been around since at least the 50's (Vic's dad even mentions getting frappes in episode 4).
Factual error: The fly Good Chucky kills bleeds red blood. Fly blood is usually clearish with a yellow and green tint. Not opaque red.
Factual error: At the end when Skeksis enters the crystal chamber, in the overhead shot you can see 22 arcane symbols around the crystal when there should only be 18, one for each exiled skeksis. (00:45:53)