There was a topic already about the problem, that PoW skill doesn't give casting speed. Yes, this skill/buff doesn't give casting speed in Interlude Chronicle, but in Gracia (maybe Kamael) and later Chronicles it gives 20% casting speed.
Once again, this is not a bug, that this skill does not give casting speed, but the description of skill is wrong. I guess the description of this skill in this server is from later Chronicles.
Interlude knowledge base:
(https://i.ibb.co/fFQ8fjv/pwind2.png)
And this is Gracia Final knowledge base:
(https://i.ibb.co/Zg0mtYH/pwind1.png)
I guess there are many skills with wrong description or not exactly the same as it works in Interlude.
There's not a big problem for this actually, just a reminder. Maybe it's because you plan to upgrade to later Chronicles in near future?
Thank you for report.
These are going to be adjusted accordingly to IL.