Brayflox Longstop NM Borked

Well this is strange really for me as I've always played as a healing role. What it Is I decided to help out a FC member with Brayflox longstop and no sooner did we enter the mobs In there seems different. Different as In they was taking half of the tanks health with on hit and I was only healing for around 200 damage a time. Now I know my toon Inside out and this shouldn't be happening. Has anyone else felt this happen because we managed to get to the first boss and bam we all met a grisly end a few time's because of the screwed up stats. Before you mention the obvious. I know how to play this class 100% and have complete faith on my role as a healer. It just knocked me for 6 that we was beaten so easy. I've done this dungeon many times before and NEVER has It been like this.