Warsong damage bug!

Does anyone in here knows anything about that bug that just halve the damage of your characters, and there's no way to repaire it. Even if you delete it and create a new, still damage is freaking halved. I trie to create two accounts, but it's the same for both. I tried warriors, death knights, hunters, shamans and paladins. For every character damage was too low. For example, my warriors mortal strike does a 11k damage to a dummy and onli 3-4k to a player. I mean, even if that bloody resilience counts, it's still 48% max damage reduce, so mortal should deal at least 6k damage. And to be worse, my friend and I were testing. His mortal strike , with the same gear, is doing normal damage of 10-12k. The same is with other abbilites with other mentioned classes. I realy want to play, but I can't with bug like this and I found out that not many people are occuring this.