I searched for all posts on carnage and this had not been reported as far as the forum search engine was able to provide.
I realize there are -similar- issues with confusion, however you can -choose- whether to plonk an AOE spell over a confused ally.
You can't choose not to trigger carnage other than let the enemy freely attack you while waiting for the charm to wear off (I don't consider that a valid workaround, you might as well say 'just reload your last save').
How is this not considered a bug? Confusion was on the ally, not the Barbarian yet it was affecting the Barbarian's ability, not the confused ally abilities.
I can understand a confused Barbarian hitting my party with carnage, but that should not go the other way.
Don't mistake that just because "this is how something works now" that it is not a bug - by that logic, there are no bugs.
That would imply it's a feature, and thus we should find documentation indicating that 'Barbarians are crazy, they will slaughter any allies who come under temporary charm effects. Do not take Barbarians in your party if you value companionship, loyalty, or your life.'
Note that I'm not talking about a bug in the party AI and an autoattack on a charmed member, this is the carnage auto-proc from hitting a (real) enemy
If you can find another bug post regarding carnage and it hitting charmed allies, please link it and we can close this one.