UPDATE: Get in contact with Customer Support and they will let you exchange and it will not count towards your one-time item exchange.
==========================We are sorry for our first negative answer, as the issue had not been confirmed by us at the time. However, after reviewing the facts we did realise that you should be able to have the possibility to exchange this item.
The bonus attributes for the items below were changed in err. They will be reverted to their original values in an upcoming hotfix.
* Added on December 16, 2013.
Allagan Circlet of Healing
Before: MND+18, VIT+18, Determination+15, PIE+11
After: MND+18, VIT+18, PIE+16, Critical Hit Rate+15
Allagan Breeches of Healing
Before: VIT+29, MND+29, PIE+26, Critical Hit Rate+24
After: VIT+29, MND+29, Spell Speed+34, PIE+18
Allagan Boots of Casting
Before: INT+18, VIT+18, Critical Hit Rate+21, Accuracy+15
After: INT+18, VIT+18, Spell Speed+21, Determination+11
This wasn't actually "added on December 16" I was checking the notes yesterday for something about Treasure Maps and there was no mention of it.
I only play BLM so I can only speak for us, but the Boots were BIS for us until the change. Many of us who owned the Boots most likely went out and bought the Mythology Boots after the patch as they had the same stats.
Now they're reverting the change, pretty much wasting a week/week and a half(on old week cap) of tomes. For example I'd much rather have the Cleric Circlet for my WHM than useless boots.
I feel this is pretty unfair. I have full 90 for BLM and the only reason I bought the Mythology boots was for the stats, I hate the appearance of them (so that's not even a reason to keep them for Vanity) but I needed the accuracy for Coil.
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To clarify: I barely use forums. I don't use Reddit. I don't read Japanese. Apparently the changes were made known to Japanese players before the patch went live, and subsequently a translator told people, and was then posted on Reddit and here for people.
The changes were not told to English players via Official Channels until last night, I check Lodestone and the Dev Tracker daily and there was no mention of the revert in-game either. I shouldn't have to get important information like this from community. It should be told to everyone in ALL languages at the same time.