The End of Flutter Valley (2) - S1-E2
Other mistake: As the Stonebacks begin to destroy the bridge the Ponies call out for help. As the bridge moves up and down, locks of Gusty and Baby Cuddles' hair flash white. Baby Cuddles is also drawn in a deformed fashion with no neck and two rumps.
Moero! Pegasus Ryuseiken - S1-E2
Other mistake: In the ending shot of the tournament bracket showing the potential future opponents, the two saints' names are written the wrong way, as "DORAGON" and "ANDOROMEDA", instead of Dragon and Andromeda. (00:22:00)
World's Greatest Grandma - S1-E13
Other mistake: A six-piece band of grandmothers is playing "When The Saints Go Marching In" at a school talent show. None of the piano keys move when the pianist taps them.
Other mistake: In a newspaper article about an overnight break-in and robbery at a bank, three paragraphs in the first column are repeated in the second column.
Other mistake: It's not possible for Holmes to remove all of his elderly bookkeeper disguise in the mere seconds Watson turned his back.