Another possibility is beardie puberty if she hasn't gone through it already. Just ignore the behavior and confuse her when she puffs up & opens her mouth at you by putting greens in her mouth. It really does help with that.
Might be a good idea to recheck the temps if you haven't lately. Sometimes they react that way if the tank is too hot & the change of seasons may mean a bulb adjustment is needed.
And like Goonie said, shedding can sometimes cause them to react differently. So, guess you have some things to rule out before you'll know the reason.
Edit: Are you using either a digital thermometer with a probe end or a temperature gun to test the temps? Also, what brand UVB are you using & is it a coil, compact, strip fluorescent or mercury vapor bulb? Has there been any change in her?