Challah braids melding together
There's nothing wrong with your dough, it looks like you are getting a good rise out of it, which is what you want. I can't see you wanting to mess with success. 

What you need to do is adjust your rolling and braiding technique to take into account how much rise you are going to get. Try rolling out your braids a bit thinner and braiding them much looser, this will give the bread more space to expand. If you need a shorter and wider end result try a 5 strand braid instead of a 3. It may take a few tries to get it right but practice in this case is perfect. 

It looks like you've got a heat problem from your picture, one of your loaves is torched! If you are using a fan oven turn the fan off and use a non-fan mode, or if that's not possible try creating a wind-break with a piece of tin foil to keep your loaves out of the direct path.