Monster.sdata doesn't contain skills. The monster skills are designated in the DB under PS_GameDefs.dbo.mobs, and that's not the same as the client-sided Monster.sdata. The only time the sdata shows the skills correctly is when you have imported the .csv tables from the DB into Castor's tool, and then it generates a MonsterEX.sdata, which *does* contain the skills.
So what you need is for someone to share their MonsterEx.sdata (with skills working 100%). If I had one of those, I would share it, but unfortunately I don't (yet). Until then, do like me and modify every new mob by hand. xD