How much did you trim and how much root ball did you move? Did you use acidic soil in the replanting area? Brown is a sign if stress. Camelia leaves going brown are normally a sign of under/over watering. Some of the lower leaves on mine have gone brown and fell off due to the recent very wet weather. I am thinking that your may be due to having too little water as you may have severed too much roots and have too much 'green' on top so the two are out of proportion.