Continuity mistake: When Shifu performs the Wuxi finger hold on Po, in one shot, we see all of Po's fingers, except the one Shifu is holding, are closed to his palm. In the next shot, all his fingers are open. (00:22:05)
Suggested correction: If you slow down before the part where the camera pans onto Po when he's surprised, his fingers open.
Continuity mistake: After Po accidentally breaks the Urn of Whispering Warriors, the broken pieces move around on the floor. (00:21:50)
Continuity mistake: When Po is trying to get into the ceremony at the beginning of the film, the fireworks attached to his chair explode and leave him with dirty white fur. After he clears the gate and gets inside to the ceremony his white fur is completely clean again.
Continuity mistake: When Tai Lung reads the Dragon Scroll, he drops it on the ground. For the rest of the scene, it's gone.
Continuity mistake: When Shifu is speaking to Oogway under the mystic peach tree, he slams the ground, causing a large number of peaches to fall. In the following wide shot, only a few peaches are on the ground - none of which are even close to Shifu, who hasn't moved very far from his original position.
Continuity mistake: When Tai Lung is at prison, and he breaks his shield-thing off, the guardians fire four arrows at him and he evades all of them. He uses the fourth and last one to break the shackle off his hand. But in the next camera angle, there are five arrows stuck in the floor. Where did the fifth one come from?
Suggested correction: The fifth arrow appears after a space of 17 seconds. During this space, not only a fifth arrow has appeared, two other crossbows are rearmed and ready to fire. It is plausible to assume the guards have done all this. This is the natural progress of the film.
Continuity mistake: When Po tries to pole-vault into the arena, there is a large spiderweb-like crack that appears in the wall when he fails. However, when Po is launched by the fireworks powered chair, he is thrown against the same wall but the crack is gone.
Continuity mistake: When Po's Dad puts the apron on his following their hug the apron appears out of nowhere, having not appeared in any previous scene.
Suggested correction: If you are talking about the event at 1:07:40, it is not a mistake; Po's stepdad put the apron on him. There is a suspicious woosh sound and Po's right eye (left side of the screen) opens in surprise. The apron also unfurls, as if it was just worn.
The mistake seems valid. When Po's dad see him, he raises his arms (wings) and his hands are empty. When he hugs Po, his arms in no way come close to wrapping around Po's belly. So why we can't see what Mr. Ping is doing during the hug, his position doesn't move, so there's no way he could tie the apron around Po if we assume he somehow had the apron in his pocket (even though there's no evidence for that).
I know. But the whoosh version that the filmmakers have chosen is more fun than your literal-minded version. It is an established tradition in cartoons to replace very fast actions with cartoonish materialization accompanied by a whoosh sound. Following that tradition is not a mistake, especially when the film is a work of fantasy.
Continuity mistake: When Shifu chops a peach for Oogway, he throws it up and slices it in half. He falls, stomps a hole into the ground, and catches the peach pit. However, the two peach halves do not fall with it.