At approximately 36 minutes, when Desdemona is using her tablet to record Freddy attempting to shoe the horse, she is holding it in landscape orientation. But in the next shot, focusing from behind where the screen is visible, the tablet is clearly in portrait orientation. In the shot immediately following, she is back to landscape.
Around 00:23:24, when Velma sneezes, her sweater is visible through her mouth.
Daphne claims that roughly 98% of Mystery Inc.'s cases involve real estate. Actually, most of their past mysteries involved stealing, revenge, and smuggling. She may have just been speaking hyperbolically.