Firstly, I just want to say thanks for releasing your code to the people. This is my new favorite hobby currently, and I am in the process of getting a full raid group together on vanilla gaming Alliance side. I have 25 characters leveled and I am just trying to get them geared enough to do ZG before I level another group of characters.
So onto the issue I am having. So for some reason whenever I go to cc a target I get an error. If I first press F7, I think F6 works as well, before pressing F1 to assign the target then it works and I don't get an error. If I do not clear the targets first I get this error. I tried looking into it myself, but I wasn't really sure what the problem was. This happens whether I am in a raid or just a party. The cc assignment still works, but only if I clear targets first.
I am also having an issue where my druids won't take their cc assignments. I press the cc button on a dragonkin and nothing happens. They have the ability skilled. I am not sure if this is related to the error or not. I think once I get this fixed I will be able to take down Rend.

This is very strange. Can you re-download the full addons release from the downloads page and try the latest lowCPU code?
It is working well for me, to the point that I one-shot every boss in MC this week except Shazzrah.
We have to get to the bottom of these user specific fails, though.
ALSO: CAN you make a discord account and join the discord server?
https://discord.gg/JcEuKjU