provided you dont press stop, it may take a little bit, but it should download all the meshes it needs for that battleground. you may have to play manually for a bit if it sits for too long but, once its completely has all the meshes it needs it should be running fine, and you wont have to worry about it.
It still does this for me sometimes also, when I've been in Eots at least 200 times within the current week. Do you have the PvP suite? It can sometimes make this happen also.