Continuity mistake: When the two children visit the Ghostbusters the little girl is wearing a pink pajama top and pink bottoms. In the next scene the pajama bottoms change color and are now orange.
The End of Flutter Valley (3) - S1-E3
Continuity mistake: When Reeka is conjuring the fake rainbow to distract the Flutter Ponies, the grey pot on her head is blue for a while.
Yomigaere! Eiyuu Densetsu - S1-E1
Continuity mistake: When Seiya reaches for the Cloth's handle, the box is approached from different sides in his POV. (00:15:50)