Two “exploits”. One is actually an exploit, the other was a bug.
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The exploit. Previously, you could find a 2h or amulet with an Aspect that gains the 50%/100% bonus. You could then upgrade the item, and the Aspect would increase in power. THEN, you could extract the Aspect and it would retain the value. Example: item with +500 barrier aspect. Find on an amulet, goes to +750. Upgrade amulet, it’s now +1300. Extract the Aspect, it stays +1300. Now put it on a new item, it stays +1300 (or goes higher to 1850 on another amulet). This one was fixed early, about a week or so after launch. I actually still have a few Aspects in my stash from this that are fairly low level with some moderately high values. I haved checked them after the last patch, but they may have decreased!
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The bug. The Codex would yield powers set to the character level, rather than the item level it was being placed on. This fix is mentioned in the patch notes.
I don’t know which the OP did, but Blizzard obviously changed it to the proper values.