I started a new storm wizard the other day and I noticed this as well, and its also with my life wizard. I've been playing with my level 89 fire, and this isn't a problem for him. I think one of the updates caused lower level wizards to have this happen to them?
It isn't a glitch. The * means you have a gear item that gives a fixed damage boost like +3 as well as one that gives a %. You'll get the % boost shown plus the extra, but there isn't space to display all that so instead of 4% + 3 it just shows 4* or whatever.