First of let me introduce my character. Her name is Orya, another one of my Alts, and is now a level 104 Engineer.
For the past 30 - 40 levels I have been using Zenith Taichi's having opted for the MA Engineer route.
After reading the forums I have noticed several people commenting on the possibility of there being a bug using the Zenith Taichi's. Here are my observations:
As I said Ive been using Zenith Taichi's for the last 30 levels at varying qaulities and I have noticed a common trend. I only get a problem when my weapon is over-quipped.
Now I know when a weapon is OE it is so many % effect, but that shouldn't stop the MA attack all together, it should mearly make it however many % effective.
When it is over-equipped I do not use my MA skill at all, and can't hit for any MA damage as well as the 1h-edged ( Zenith ), I only hit for 1h-edged damage.
When the sword is 100% then I do both MA damage and 1h-edged.
This theory has been tested at various levels of my characters life, and using various QL Taichi's, and always seems to be the same.
Over-Equipped - only 1h-edged damage.
100% - Effective 1h-edged and MA damage.
My advice would be to make sure your weapon is always 100% effective until Funcom have addressed this problem.
Can other people please feed back on this, let me know your findings... I would like to see these swords working properly, they aren't common in game, yet they are VERY good weapons, and would be made even better if this bug could be fixed.