Root + FD drops aggro while mob rooted

[SantagarBrax]

It's not consistently blurring and these are mobs over lvl 35. I'd say 1/10 or so.

Is there historical patch notes regarding mem blur on rooting mobs, whether on spawn or not? I don't recall FD dropping aggro on a rooted target back on Live in era. Could just be my memory though. I seem to recall if you stand while target is rooted, you wouldn't clear off the hate list for the duration of the root.