First, thanks for all the hard work, and I'm confident that this will be a truly great addon once all the issues have been sorted out.
Now to my problem. I noticed a strange behaviour when running Kara as a druid tank tonight. Everytime I engaged a mob that had been CC:ed (shackled in this case) I would get an insanely high aggro spike and anyone else attacking the same mob would be shown as having 0 threat relative to me. Mobs engaged directly without cc:ing first worked fine.