Seriously, I noticed a clear damage nerf on my chaos bolts, and i´m not talking about the 25% dot thing.
Doing some random BGs this week after 5.1, some chaos bolts would sometimes hit decent geared players for around 50k, my gear is all dreadfull and 1 malevolent piece. It never did anything less than 70k before.
Doing some testing on dummies I saw a damage decrease too. I´m pretty sure they stealth nerfed CB damage.