Continuity mistake: When Kenai and Nita reunite, there are two broken spear pieces on the ground. Halfway through the scene, one of the pieces disappears.
Continuity mistake: Near the end, Nita tears off her sleeve to use as a bandage for Kenai. At one point, she drops it and it's gone for the rest of the scene.
Continuity mistake: During the racoon scene, Nita completely disappears in wide shots.
Continuity mistake: When Nita's bag washes ashore after falling down the waterfall, it washes up very close to the water. But in the next shot, it has moved farther away from the water.
Continuity mistake: When Koda "scares" Nita with the fish, she drops the fish in the water. But later, the fish is back on the shore.
Continuity mistake: At the end, when Kenai and Nita's fiance are fighting on the cliff, the sun is just starting to set. But the instant Kenai falls off the cliff, it's completely dark.
Continuity mistake: When Nita shows the amulet to Kenai, it's oval shaped. But for the rest of of the movie, it's circle shaped.
Continuity mistake: In the scene where Nita goes to see the sha-woman, at one point, the sha-woman drops her horn. In the next shot, the horn is gone.
Continuity mistake: When we first meet Nita, we see a wide shot of her village. At her wedding, the village is covered in snow even though earlier it was completely dry.
Continuity mistake: At the end, we see a wide shot of Kenai and Nita's wedding. A few seconds later, we see Nita walking down the aisle. Given where she was standing, we would've seen her in the wide shot. But we don't see her at all.
Chosen answer: Probably for just that reason - they were waiting for the right moment to change Kenai back.