Ok, got my set replaced by Ant today! Thank you. Ant removed the "Plot Item" for me and I was able to forge the chest. Did some testing and here is what I am seeing
First, when I talked to Ant about the Enhancement bonus affecting Ranged touch attacks (rumor of lowering it in some older posts), I did not notice that. I bought the Practiced Invoker Scepter from the Jeannie. It had +2 Enhancement Bonus not Attack Bonus. When I tested on a few mobs with no weapon, I was getting +38 to ranged tough attack, with it equipped I was getting +40. I went and forged it to +10 enhancement and got +48 ranged touch on the same mobs. So Enhancement seems to affect Ranged touch attacks, AB bonus I did not check yet. Getting to broke to re-forge =)
For the set, I still do not see Practiced Invoker, Empower Eldritch Blast or Maximize Eldritch Blast on any of the pieces and they are not on the feat list anywhere under character description. There is also a repeatable bug to increase your hit points. Every time you wear the set, once the bonuses kick in, remove the chest, wait a sec or 2, re wear the chest and watch the bonuses get listed again and your hit points keep increasing. Every time you remove it and re equip it you get more and more hit points. I tried showing a screenshot of my Warlock with over 3,000 hit points but the file is to large. If you need to see it, pm me and I can email it to you. When I logged out and back in, it showed me with 3174/744 hit points because the bonuses had not kicked in. I rested and my hit points went back to 744/744, which did not have any bonuses from the set. You have to remove an item and re equip it to get the bonuses to kick in.
Next up is the special ability Warlock pet. If you look at his feats, he has the Epic Hellball spell. I have never seen him cast this, I have changed his settings all over the place, to overcasting, conservative etc. but he wont ever seem to cast it. He also has Divine Might, but never seems to use that either no matter what settings he is on. Anyhow that's all so far I can see. Suggestion to remove Epic Hellball spell and give him Quake Shock ability since he is more of a melee tank than a caster. Would help a bit with crowd control, just an idea.
That's all I have found so far, will test some more later.