Revealing mistake: When Ayla is looking at her "ugly" reflection in the lake she moves her hand down and a second later the reflection moves its hand down.
Revealing mistake: When Ayla gets her leg cut by the lion, the claw that cuts her doesn't look like a lion's paw (it looks like a bear) and you can see the "blood" is already on the paw and coming out of it as it dragged across her legs.
Answer: The only reason I (and anyone I asked) could find was that, as usual, they discarded the ending though emotionally intense for the sake of another climax full of physical violence after the belief that this is the type of endings people prefer in the movies. Really sad indeed.