Sunscreen Has Mind Of Its Own!

The automatic sunscreen on my 2012 Avalon seems to have a mind of its own. I fully understand how it is supposed to work: press button to raise shade; when the car is in reverse, the shade goes down and will automatically raise again at 8 mph. Fine....however, mine will activate on its own. It seems that in the summer weather, the sunshade will raise without being activated. My local Toyota service advisor had never heard of this problem...Sure he hasn't. The Woners' Manual states that the dealer can reprogram it. I have an appointment next week to see if they can find a code to reprogram. I'm thinking it is set to activate at a certain temperature, ie. 85 degrees, as it does not seem to do this during cooler weather or when not in direct sunlight. aNY SUGGESTIONS OR COMMENTS?