Authenticator giving wrong code often

My authenticator seems to "lock up" every so often, especially in the morning. I will go to log on, activate the authenticator and the code it provides is not accepted by the log in screen. During subsequent log in attempts it appears that the code on the authenticator does not change for several presses of the button (I have the keychain model). After a minute or so, sometimes longer, the authenticator will return a code that is finally accepted by the log in screen. It seems to be getting worse as of late. The first time it happened I assumed my password was the issue so I reset it, still no change, got locked out due to multiple attempts. Finally called Blizzard and they reset it. Now its starting to fail again. Please advise.