Evolution! That Mystery and Wonder!! - S8-E50
Revealing mistake: When Caterpie leaves the laboratory, it clips through it. (00:09:20)
Revealing mistake: When Ash is first seen, his hands clip through him. (00:00:02)
Electric Shock Showdown - S1-E14
Revealing mistake: When Nurse Joy says, "A while ago, I came across something like this," a line on her dress shows through her clipboard despite covering it. Also, her left sleeve goes from being absent to being visible. Additionally, her right thumb is not covered by her case, but in the next shot, it is. Furthermore, her left arm is angled up, but in the next shot, it is angled down. (00:11:08)
Mystery at the Lighthouse - S1-E13
Revealing mistake: When first showing Ash and friends at the top of the lighthouse, Pikachu is floating in midair. (00:15:00)
Revealing mistake: When Nurse Joy is in the emergency room, a light is floating in midair without being attached to anything. Also, a left door goes from being absent to being present. (00:06:31)
Revealing mistake: When Ash says, "Seems almost magical," the end of Pikachu's tail is missing. (00:03:59)
Banana Namakero Park and Kabigon!! - S7-E48
Revealing mistake: When Ash puts his hands on the gate, some of his fingers clip through it. (00:02:27)
Revealing mistake: When first revealing a Lotad, the Lotad appears from nowhere. (00:02:10)
Revealing mistake: When one of the staff of the Pokémon League goes over to type on the keyboard, she clips through a device in the process. (00:02:40)
Answer: Yes it ran away because Layla hurt its feelings.