Insane damage on Ob's Cannibal Blade

The notorious monster Ob has been exhibiting an insane increase in damage when it uses a particular weaponskill (Cannibal Blade), since a few months, with damage exceeding 20000 at times. This used to deal medium damage (~400) before.
No official update notices I've seen reported anything about this particular NM being changed, nor are there are update notices mentioning this problem as being acknowledged yet.

Platform: Windows XP
ISP: Online
Type of Internet Connection: DSL
Internet Connection Speed: 10Mbps
Date & Time: December 11th, 2011 between 22:00~23:00 CET
Frequency:Always
Character Name:Kristal
Race:Hume F
World: Bismarck
Main Job: PUP
Support Job: /NIN
Area and Coordinates: Alzadaal Ruins
Party or Solo:Solo
NPC Name: None
Monster Name: Ob

Steps:
1. Spawned Ob by trading Cog Lubricant to ???.
2. Engaged Ob with Soulsoother Automaton.
3. Used Light, Fire, Light Maneuvers to force Ob to switch to Valoredge Frame.
4. Ob's melee hit removed last utsusemi shadow.
5. Ob's next melee hits interrupt Utsusemi cast.
6. Which was immediately followed by Cannibal Blade, dealing 21000 damage.

Screenshot of the deathblow:
http://i43.servimg.com/u/f43/14/03/89/09/ob_is_10.png
The 24 dmg hit just before Cannibal Blade was Guarded.

Greetings Kristal!

Thank you for posting all the details and required information. It's best to report issues like that to use since we would not want it happening to others, so it is appreciated! Since we have all the information needed, we will forward the report to be investigated. Any updates throughout the investigation may be posted within the forums.

Thanks again!