Well, wouldn't you be mad at your bother sister sometimes?? it's the same is not always laughs and smiles, even if they don't like each other anymore they are teens and that's enough trouble.
I don't think that they hate each other it's just that they are in a complicated age unlike other groups that are in their 20's and more mature.
In the first video, Camila apologizes and Lauren smiles back saying "it's okay".
In the second one, Camila steps on Lauren's dress.
In the third one, Lauren just looks unconfortable with the whole situation.
Last, Lauren and Camila have to adjust their poses in order not to cover each other.
This is such a poorly edited video.
But get that hit thread, I guess?