I didn't have it but my girlfriend did. One time she had to reboot her console before it stopped. Her dps readings wouldn't change unless she went in and out of her menu then wouldn't change at all.
Also one time I was playing music through my xbox music, a lot. Pictures in my inv didn't load properly untill I shut off the xbox music.
Since it's been happening have you rebooted your console? A reboot may fix it and it may not even be a physical change but just a bug in the reading. As when her dps wouldn't change for her I could still see the change and tell her it through the view inv menu.
I'd venture to ask if its any kinda buffs from barb you forget you have but reequipping wouldn't fix it then. (I've forgotten I had Frenzied from shrine or the overpower buff)
Witch Doctor Lv60 (237k dps)
Monk Lv35 (only with gf)
Wizard Lv43 (only with gf)
Demon Hunter Lv4 (only with gf)
Barbarian Lv60 (328k dps)