raid behavior

This is going to be long. I am trying to see if anyone else is having the same issue we are. Over the past 10 days or so, our Hpit has been increasing in difficulty. People who could normally solo the raid consistently no longer can. Others have experienced a drastic drop in damage. Example... I can normally post anywhere from 8 mil to high 9 mil and have been able to do so consistently since the zader bug fix. The past several raids I have dropped in damage every single raid. From 8.9 mil, to 7.2 mil, to 5 mil, and today to 3.9 mil. Our teams and mods are all the same. There also have not been any changes to the characters that we are using or an announcement that the Hpit stats were going to be changed. Now for the really strange part. When I practice the raid during our Zero damage period I can consistently make it to 70% to 30% of phase 4. When its the scheduled raid time we experience a difficult rancor like we have never seen before. We are hoping to find out if anyone else is experiencing these same issues. We cannot figure out what is going on. It seems a little to severe to be RNG. We don't know if we have a bug, there has been an Hpit stat change, or even worse one of our guildmates hacked the rancor somehow. Any insight would be helpful. Thank you community.