Durinn Amber Weakness Triggering

Platform: Windows
ISP: Time Warner
Type of Internet Connection: Cable Internet
Internet Connection Speed: No idea
Date & Time: Apr. 17, 2011 23:00~ Mountain Time
Frequency: Once (But likely to happen more often)
Character Name: Garota
Race: Tarutaru Female
World: Ragnarok
Main Job: BLM90
Support Job: RDM
Area and Coordinates: Abyssea - Vunkerl, E-12
Party or Solo: Alliance of um... 10 members?
NPC Name: None
Monster Name: Durinn
Steps:

1. Built our key items to go for killing Durinn for some Jewels.
2. Popped multiple Durinns.
3. Some Durinns had Discernment message informing us that it was weak to Dark Based Magic.
4. We could not trigger weakness on only one of the Durinn, even with a BLM with BRD subjob has his Light Threnody with Elemental Seal resisted, our Ninja would not land Kurayami: Ni and my Dispel was resisted as well.
5. I mentioned it was okay that we could not land our spells and just to be happy that SE will be removing 8 BLU spells from weakness triggering list.
6. We proceeded to kill Durinn without the amber weakness triggered.

Hey there Garota!

Thank you for taking the time to fill out all the information we need. We apologize for any trouble the weaknesses not triggering caused, I can see it being a lot more difficult if everything just got resisted. We'll be happy to forward the concern to try and get it resolved. Any updates will be posted within the forum as they become available. Thanks again!

Greetings, Garota!
Thank you for your patience with the wait for a response to your report. After investigating this matter thoroughly, the development team did not find any problems with Durinn, since it seems that there may have been some confusion about the properties of Light Threnody. If you continue to have trouble with Durinn, though, please make sure to submit another detailed report in a new thread about your experiences. Thanks again for your patience!