Game glitch

avixer

I don't know how or why I have received 2 mastery points on level up from 40 -41.I had already purchased 3 mastery cores..I used my 1st mastery point for unlocking the Physical resistance.But when I was going to unlock Dexterity(costs 2 stony mastery cores)it said I've no items to unlock the mastery that means I've no stony mastery cores but in my inventory I can see my previously purchased 3 mastery cores....What happened.....Is that a glitch or some other stuff ......Please tell me.......