Tomtom one 3rd Edition touch screen jumps crazy in the sun

[sfcdmu]

I have this unit about 6 months. The unit works fine at nights or cloudy days, but when driving with sun shining on the screen for a few miniutes , the screen starts to jump randomly to different manu options, letters or numbers, and randonly changed the settings and input letters when the unit speaks. The custom support people asked me to update the software and the problem still not solved but getting worse in hot days. Should I ask them to take it back for repair, I think this is a hardware problem.