Before the change in the pre-patch event, I could enchant my Dalaran Defender’s headpiece gear with Incandecents Essence item from DF raid.
But now it does not work at all, no error or text shown why it does not work.
I have tried to enchant other headpieces and that worked, also tried on a wow installation without any addons without luck.
The Dalaran defenders Headpiece is technically not a DF item, but a TWW item.
I´m 99% sure that´s the root cause. Whether it should stay that way or not is of course debateable…I´m actually surprised that it was possible before…
From my understanding there is no limitation on the enchantment item that says its only for DF items. I also seen posts about this item being good to get now to have in TWW. Anyways as said, it worked on the prepatch items prior to Blizz changing the event. I see that in Wow Armory it just says “Enchanted:” but not the enchantment.
I uploaded a screenshot on Imgur but I’m not allowed to add a link in the response, but if you look up Incandecents Essence on Wowhead there is a link in the comments there
Use the “preformatted text” option, then you can still post links. At our trust levels we just can´t post directly clickable links to untrusted sources. That said it´s not hard to open the armory and see that both your Wyrmforged helm and my Lost Scholars hat are merely “enchanted”
But I’m curious as to where the info to get it for being useful in TWW is from, because at least on beta I can´t use it on TWW helms (which is why I assumed that it “shouldn´t” work on prepatch gear)… People might be banking on a bug to exploit on that one…
So I may have jumped the gun-ish here abit.
The two prepatch helms I have with the enchant was both upgraded on drop to Champion ilvl493. These work to re-enchant over and over.
But the Veteran ilvl480 does not work, so that maybe has been the case from the start.
Though that´s also an interesting inconsistency, that the Champion version can be enchanted and the Veteran can’t… 0.o
Jupp agree that its a weird inconsistency 
The enchant itself is ilvl 489 so could be that its not allowed to be used on items with lower iLvl than itself.
Will update the title to better reflect this