Character name is "apparently" I obtained the skill when I advanced to 4th job bishop at lvl 120. I am currently lvl 129
I presume that you got the Maple Warrior skillbook via the NPC after advancing correct? And then double clicked the book? Can you please give us an approximate date as to when you double clicked the book as this will help us understand the issue much better.
I honestly don't remember clicking a skillbook specifically for the skill MW, but I do remember clicking a brown skill book after getting the 4th job and unlocking some skill (it probably was MW ). I got my 4th job advancement along with MW only a few days before the new source maintenance (~Dec 30, 2016). I also never attempted putting any skillpoints into MW during the old source. Only after when I had extra SP to spare did I try to and found it didn't work (around Jan10-13).
https://gyazo.com/b84be969a32d350fffb6d4592b773f72 ^ ss of my MW I saw the other person's thread about mastery level being 0. Mine is level 10, if that helps
I used a skillbook (ice demon) around 6 hours ago as of this post, and i have the same problem. The button is orange and it says mastery level: 10, but nothing happens when i click on the button. I tried adding a point into mana reflect, which ive had at lv0 since summer, and that worked fine. Currently have 35 skillpoints available. Hope this helps