So weird bug me and one of my guildies noticed last night.
We run different damage meter addons (Me with Details!, her with Recount) and we both saw her doing 166k and me doing 124k on Mythic Manno. However when we looked at WCL it had her at 128k and me at 98k. We couldn't figure out why. It did something similar on Mythic Archi immediately after.