I’ll keep an eye on this question, and will play a bit more with this instance / character to see if I can isolate an activity. I’m pretty sure that the grade of the armor matters less than the set. Though I can’t speak towards differences between Epic and Non-Epic. They probably use the same graphical elements, but your question helped me to answer with more specifics.
Until then, I have more issues to get logged. Hopefully they are relevant and useful.