I hope this is an isolated incident, and NC does not fall into the habit of making changes to the rules of the game without warning. :(

[update]: Melantus, Lineage Community Coordinator, was kind enough to post on this topic on the official message boards (on Sunday no less). Here's what he had to say:

It looks like some changes went in to the mana staff that were unintended. Initially, they were changes in a test form that we decided not to impliment. Somehow, they got publish to the regular US servers. Right now, we are looking into it a bit further. If there was a necessary reason that these changes had to go in, I'll come and explain why on the boards here. I want to be sure that we explain as much as possible changes of this type, if they are necessary or needed. Sorry about that. :)